Debugging
debugging a project as large as mozilla can be a daunting task.
... fortunately, over the years, mozilla developers have come up with not just technologies and features to help you debug code, but have devised tips and techniques that can help too.
... also available are assorted tools that you can use when debugging.
...And 20 more matches

Debugger.Environment - Firefox Developer Tools
a debugger.environment instance represents a lexical environment, associating names with variables.
... each debugger.frame instance representing a debuggee frame has an associated environment object describing the variables in scope in that frame; and each debugger.object instance representing a debuggee function has an environment object representing the environment the function has closed over.
... spidermonkey creates debugger.environment instances as needed as the debugger inspects stack frames and function objects; calling debugger.environment as a function or constructor raises a typeerror exception.
...And 17 more matches

Debug.writeln - Archive of obsolete content
the debug.writeln function sends strings to the script debugger, followed by a newline character.
... syntax debug.writeln([str1 [, str2 [, ...
..., strn optional strings to send to the script debugger.
...And 10 more matches

Debugging a XULRunner Application - Archive of obsolete content
the easiest way to debug a xulrunner application is to get the system to tell you what's wrong!
... see also debugging javascript prefs setting the following prefs will make your debugging life much easier!
...it doesn't matter what the file is called (as long as the extension is .js), so debug.js is as good as any!
...And 9 more matches

Debug.write - Archive of obsolete content
the debug.write function sends strings to the script debugger.
... syntax debug.write([str1 [, str2 [, ...
..., strn optional strings to send to the script debugger.
...And 9 more matches

Debugging JavaScript
it should give pointers to tools, aids and tricks which make debugging your code easier.
... web console this is the first place to go when you're debugging a web page; open the web console using the web console option in the web developer menu.
...to enable it, go to about:config in the url bar and set devtools.chrome.enabled to true, or set the "enable chrome and add-on debugging" option in the developer tool settings.
...And 8 more matches

Remotely debugging Firefox for Metro - Archive of obsolete content
this article explains how to use remote debugging to inspect and code running in the new windows 8 ("metro-style") firefox app, using the developer tools in firefox on the desktop.
... set up firefox for metro go to about:config in firefox for metro, and set the following required preference: devtools.debugger.remote-enabled = true you may also want to set these optional preferences: devtools.debugger.force-local = false (if you want to connect from a different machine over the network) devtools.debugger.remote-host (to change the tcp hostname where firefox will listen for connections) devtools.debugger.remote-port (to change the tcp port number where firefox will listen for connections) dev...
...tools.debugger.prompt-connection = false (allow connections without displaying a confirmation prompt.
...And 7 more matches

Debugging OpenGL
for various reasons, debugging opengl related code can be tricky.
... this article provides suggestions for how to improve your efficiency while debugging opengl code in gecko.
... opengl debug mode when running a debug build, you can enable the opengl debug mode by defining the environment variable moz_gl_debug.
...And 7 more matches

Remote debugging - Archive of obsolete content
when a bug is reproducible by a community member, but not on a developer's computer, a last-resort strategy is to debug it on the community member's computer.
... the crash victim should at least know how to run a debugger, if not how to use it, and should have a debug build of firefox handy.
...it allows you to see the crash in a debugger even after the program has long exited.
...And 5 more matches

Debugging HTML - Learn web development
objective: learn the basics of using debugging tools to find problems in html.
... debugging isn't scary when writing code of some kind, everything is usually fine, until that dreaded moment when an error occurs — you've done something wrong, so your code doesn't work — either not at all, or not quite how you wanted it to.
... debugging doesn't have to be scary though — the key to being comfortable with writing and debugging any programming language or code is familiarity with both the language and the tools.
...And 5 more matches

IJSDebugger
js/ductwork/debugger/ijsdebugger.idlscriptable provides the javascript debugger service.
...see the javascript debugger api guide for details.
... 1.0 66 introduced gecko 9.0 inherits from: nsisupports last changed in gecko 9.0 (firefox 9.0 / thunderbird 9.0 / seamonkey 2.6) implemented by: @mozilla.org/jsdebugger;1 as a service: var jsdebugger = components.classes["@mozilla.org/jsdebugger;1"] .createinstance(components.interfaces.ijsdebugger); note: you should almost never directly use this service; instead, you should use the javascript code module that does this for you.
...And 5 more matches

Debugging service workers - Firefox Developer Tools
in this article we will look at debugging service workers using the firefox devtools application panel.
...if this is not enough to help you figure out the problem, you could also try going to the javascript debugger and stepping through your code to pinpoint exactly where it is going wrong.
... debugging your service worker in any case, when the service worker is successfully registered, you'll see information about it displayed in the application > service workers view (along with any other service workers registered on the same domain): this gives you a variety of information about your service worker: the url that the service worker is registered on.
...And 5 more matches

The Firefox JavaScript Debugger - Firefox Developer Tools
the javascript debugger enables you to step through javascript code and examine or modify its state to help track down bugs.
... you can use it to debug code running locally in firefox or running remotely, for example on an android device running firefox for android.
... see remote debugging to learn how to connect the debugger to a remote target.
...And 5 more matches

JavaScript Debugger Service - Archive of obsolete content
in firefox versions prior to gecko 33 (firefox 33 / thunderbird 33 / seamonkey 2.30), the javascript debugger service (or simply jsd) used to be an xpcom component that allows the tracking of javascript while it was being executed in the browser.
... however, jsd has been removed in favor of the debugger api.
... var jsd = components.classes["@mozilla.org/js/jsd/debugger-service;1"] .getservice(components.interfaces.jsdidebuggerservice); jsd.on(); // enables the service till firefox 3.6, for 4.x use asyncon if (jsd.ison) jsd.off(); // disables the service hooks jsd operates using the events hook mechanism.
...And 4 more matches

Debug.msTraceAsyncCallbackStarting - Archive of obsolete content
the debug.mstraceasynccallbackstarting function associates the callback stack with a previously specified asynchronous operation.
... syntax debug.mstraceasynccallbackstarting(asyncoperationid) parameters asyncoperationid the id associated with the asynchronous operation.
... remarks call this function in the callback function for the asynchronous operation after the call to debug.mstraceasyncoperationcompleted.
...And 4 more matches

Debug.msTraceAsyncCallbackCompleted - Archive of obsolete content
the debug.mstraceasynccallbackcompleted function indicates that an asynchronous operation has completed.
... syntax debug.mstraceasynccallbackcompleted() parameters asyncoperationid the id associated with the asynchronous operation.
...if not specified, debug.ms_async_op_status_success is used.
...And 4 more matches

nsIDebug
xpcom/base/nsidebug.idlscriptable provides debugging support for scripted languages, such as javascript, java, python, perl, and so forth.
... inherits from: nsisupports last changed in gecko 1.7 note: c/c++ consumers who are planning to use the nsidebug interface with the @mozilla.org/xpcom;1 contract should use ns_debugbreak() from xpcom glue instead, or alternatively the ns_abort, ns_assertion, ns_break, and ns_warning macros, which also call ns_debugbreak() if used in a debugging build.
... assertion() shows an assertion and triggers optional behavior based on the xpcom_debug_break environment variable, defaulting to calling break() on windows and os/2 and warning on other platforms.
...And 4 more matches

Debugging Firefox Desktop - Firefox Developer Tools
this guide explains how you can use the firefox developer tools to debug a different instance of desktop firefox running on the same machine.
... in this guide, the instance of firefox being debugged is called the debuggee, and the instance of firefox doing the debugging is called the debugger.
... enable remote debugging first, you'll need to ensure that both debugger and debuggee have the "enable browser chrome and add-on debugging toolboxes" and "enable remote debugging" settings checked in the developer tools settings.
...And 4 more matches

Debugging Frame Reflow
general overview the frame reflow can be logged with the debug capabilities implemented in nsframe.cpp.
...element width maximum width frame status overflow area getting the log make sure that your build is a debug build (in short you need ac_add_options --enable-debug in your .mozconfig file).
... run the debug build, saving stdout to a file.
...And 3 more matches

Debugging Table Reflow
reflow the most efficient tool to claim that html-table code is the victim and not the source of layout bugs is a frame reflow debug log.
... block reflow another way to debug the reflow process is implemented inside nsblockframe.cpp.
... it can be invoked by set gecko_block_debug_flags=reflow the available options are: reflow really-noisy-reflow max-element-size space-manager verify-lines damage-repair lame-paint-metrics lame-reflow-metrics disable-resize-opt these options can be combined with a comma separated list messages generated by the reflow switch: block(div)(1)@00be5ac4: reflowing dirty lines computedwidth=9000 computedheight=1500 this message is generated inside of nsresult nsblockframe::reflowdirtylines(nsblockreflowstate& astate) it first shows the block id and address and then the computed width and height from the htmlreflowstate.
...And 3 more matches

debugger - JavaScript
the debugger statement invokes any available debugging functionality, such as setting a breakpoint.
... if no debugging functionality is available, this statement has no effect.
... syntax debugger; examples using the debugger statement the following example shows code where a debugger statement has been inserted, to invoke a debugger (if one exists) when the function is called.
...And 3 more matches

Debugging CSS - Learn web development
this article will give you guidance on how to go about debugging a css problem, and show you how the devtools included in all modern browsers can help you to find out what is going on.
... you can use this to do an a/b comparison, deciding if something looks better with a rule applied or not, and also to help debug it — for example if a layout is going wrong and you are trying to work out which property is causing the problem.
... the following video provides some useful tips on debugging css using the firefox devtools: editing values in addition to turning properties on and off, you can edit their values.
...And 2 more matches

nsIDebug2
xpcom/base/nsidebug2.idlscriptable adds access to additional information in debug builds of mozilla code by expanding upon the features in nsidebug 1.0 66 introduced gecko 1.9.2 inherits from: nsidebug last changed in gecko 1.9.2 (firefox 3.6 / thunderbird 3.1 / fennec 1.0) attributes attribute type description assertioncount long the number of assertions since process start.
... this is normally zero in release builds, but does include calls to nsidebug.assertion().
... isdebugbuild boolean whether xpcom was compiled with debug defined.
...And 2 more matches

Debug.msUpdateAsyncCallbackRelation - Archive of obsolete content
the debug.msupdateasynccallbackrelation function updates the relationship status between a synchronous work item and the associated asynchronous operation.
... syntax debug.msupdateasynccallbackrelation(relatedasyncoperationid, relationtype) parameters relatedasyncoperationid the id associated with the asynchronous operation.
... the possible values for relationtype include: debug.ms_async_callback_status_assign_delegate debug.ms_async_callback_status_join debug.ms_async_callback_status_chooseany debug.ms_async_callback_status_cancel debug.ms_async_callback_status_error for more information, see debug constants.
... note: some debugging tools do not display the information sent to the debugger by this function.

Debug.setNonUserCodeExceptions - Archive of obsolete content
the debug.setnonusercodeexceptions property determines whether any try-catch blocks in this scope are to be treated by the debugger as user-unhandled.
... syntax debug.setnonusercodeexceptions [= bool]; remarks if this property is set to true within a given scope, the debugger can then choose whether to take some specified action on exceptions thrown inside that scope: for instance, if the developer wishes to break on user-unhandled exceptions.
... for more information on debugging, see the active script debugging overview.
... (function () { debug.setnonusercodeexceptions = true; try{ var x = null; x.y(); } catch (e) { // catch the exception.

Using the Debugger map scopes feature - Firefox Developer Tools
this feature is useful when debugging source-mapped code.
... open the example page and then open the debugger using tools > web developer > debugger (or press ctrl + i and then select the debugger).
... the debugger opens the file "increment.js" so you can view the original code.
... using this feature is expensive in terms of resources, but it certainly makes your life easier when you have to debug source code that has been packaged webpack or a similar tool.

console.debug() - Web APIs
the console method debug() outputs a message to the web console at the "debug" log level.
... the message is only displayed to the user if the console is configured to display debug output.
... syntax console.debug(obj1 [, obj2, ..., objn]); console.debug(msg [, subst1, ..., substn]); parameters obj1 ...
... specifications specification status comment console apithe definition of 'console.debug()' in that specification.

WEBGL_debug_renderer_info - Web APIs
the webgl_debug_renderer_info extension is part of the webgl api and exposes two constants with information about the graphics driver for debugging purposes.
...generally, the graphics driver information should only be used in edge cases to optimize your webgl content or to debug gpu problems.
... examples with the help of this extension, privileged contexts are able to retrieve debugging information about about the user's graphic driver: var canvas = document.getelementbyid('canvas'); var gl = canvas.getcontext('webgl'); var debuginfo = gl.getextension('webgl_debug_renderer_info'); var vendor = gl.getparameter(debuginfo.unmasked_vendor_webgl); var renderer = gl.getparameter(debuginfo.unmasked_renderer_webgl); console.log(vendor); console.log(renderer); specifications ...
... specification status comment webgl_debug_renderer_infothe definition of 'webgl_debug_renderer_info' in that specification.

Building Firefox with Debug Symbols
by default, a release build of firefox will not generate debug symbols suitable for debugging or post-processing into the breakpad symbol format.
... ac_add_options --enable-debug-symbols this can optionally take an argument for the type of symbols that need to be produced (like "-g3").
...this value takes precedence over the flags set in moz_debug_flags note that this will override the values provided for cflags and cxxflags.

nglayout.debug.disable xul fastload
the preference nglayout.debug.disable_xul_fastload controls whether or not xul fastload is used.
... never set nglayout.debug.disable_xul_fastload to true in a production environment; it exists solely to aid in debugging.
... type:boolean default value: false (true in debug builds) exists by default: yes application support:?

Debug eval sources - Firefox Developer Tools
you can debug javascript code that is evaluated dynamically, either as a string passed to eval() or as a string passed to the function constructor.
...this source is then listed in the source list pane, and can be opened and debugged like any other source.
... the debugger will also stop at debugger; statements in unnamed eval sources.

WEBGL_debug_shaders.getTranslatedShaderSource() - Web APIs
the webgl_debug_shaders.gettranslatedshadersource() method is part of the webgl api and allows you to debug a translated shader.
... syntax gl.getextension('webgl_debug_shaders').gettranslatedshadersource(shader); parameters shader a webglshader to get the translated source from.
... examples var canvas = document.getelementbyid('canvas'); var gl = canvas.getcontext('webgl'); var shader = gl.createshader(gl.fragment_shader); gl.shadersource(shader, 'void main() { gl_fragcolor = vec4(gl_fragcoord.x, 0.0, 0.0, 1.0); }'); gl.compileshader(shader); var src = gl.getextension('webgl_debug_shaders').gettranslatedshadersource(shader); console.log(src); // "void main(){ // (gl_fragcolor = vec4(gl_fragcoord.x, 0.0, 0.0, 1.0)); // }" specifications specification status comment webgl_debug_shadersthe definition of 'webgl_debug_shaders.gettranslatedshadersource' in that specification.

WEBGL_debug_shaders - Web APIs
the webgl_debug_shaders extension is part of the webgl api and exposes a method to debug shaders from privileged contexts.
... methods webgl_debug_shaders.gettranslatedshadersource() returns the translated shader source.
... specifications specification status comment webgl_debug_shadersthe definition of 'webgl_debug_shaders' in that specification.

Debug worker threads - Firefox Developer Tools
the debugger shows the source code for all running worker threads — web workers, service workers, etc.
... you can set a breakpoint (or logpoint) on any active worker thread: when execution is paused in a worker thread, the context of the debugger is updated to show the correct breakpoints, call stack, etc., just as you'd expect.

Access debugging in add-ons - Firefox Developer Tools
the following items are accessible in the context of chrome://browser/content/debugger.xul (or, in version 23 beta, chrome://browser/content/devtools/debugger.xul): window.addeventlistener("debugger:editorloaded") - called when the read-only script panel loaded.
... window.addeventlistener("debugger:editorunloaded") relevant files: chrome://browser/content/devtools/debugger-controller.js chrome://browser/content/devtools/debugger-toolbar.js chrome://browser/content/devtools/debugger-view.js chrome://browser/content/devtools/debugger-panes.js unfortunately there is not yet any api to evaluate watches/expressions within the debugged scope, or highlight elements on the page that are referenced as variables in the debugged scope.

Open the debugger - Firefox Developer Tools
there are three ways to open the debugger: select "debugger" from the web developer submenu in the firefox menu (or tools menu if you display the menu bar or are on mac os x) press ctrl + shift + z on windows and linux, or cmd + opt + z on macos (starting in firefox 71; prior to firefox 66, the letter in this shortcut was s).
... press the menu button ( ), select "developer", then "debugger".

Automatically Handle Failed Asserts in Debug Builds - Archive of obsolete content
as of 2004-12-8, it is now possible to automatically handle failed asserts in debug builds of mozilla for windows.

Running Windows Debug Builds Downloaded From Tinderbox - Archive of obsolete content
if you run the windows debug builds you will often get "this application has failed to start because the application configuration is incorrect..." this is because the debug builds need the msvc80 crt debug dlls.

Debug.msTraceAsyncOperationStarting - Archive of obsolete content
debug ...

Debugging Internet Explorer
edgehtml lets you extract various debugging dumps through a special webdriver ms/dumpinternal url.

Debugging Safari
to enable the very useful debug menu in safari use the following: defaults write com.apple.safari includeinternaldebugmenu 1 it is often useful to switch into single process mode by turning off "use multi-process windows" ...

Debugging update problems
checking update requests if you're debugging the application update feature in firefox or other mozilla applications, you may need to see what requests are occurring.

Debugging a hang on OS X (Archived)
see also debugging on mac os x ...

nglayout.debug.disable_xul_cache
(default) see also: http://kb.mozillazine.org/nglayout.debug.disable_xul_cache ...

Debugging out-of-memory problems
this article explains how to debug such problems.

Debugger keyboard shortcuts - Firefox Developer Tools
note: before firefox 66, the combination ctrl + shift + s on windows and linux or cmd + opt + s on macos would open/close the debugger.

Remote Debugging - Firefox Developer Tools
you can use the firefox developer tools on your desktop to debug web sites and web apps running in other browsers or runtimes.

Index - Firefox Developer Tools
you can use them to examine, edit, and debug html, css, and javascript.
... 11 application application, debugging, devtools, firefox, guide, manifests, service workers the application panel provides tools for inspecting and debugging modern web apps (also known as progressive web apps).
... 12 debugging service workers application, devtools, firefox, guide, service workers in this article we will look at debugging service workers using the firefox devtools application panel.
...And 70 more matches

Venkman Introduction - Archive of obsolete content
the javascript debugger, also called venkman, has been a part of the mozilla browser and the community of web and script developers there for some time.
... this article provides an overview and some practical examples of using the javascript debugger in web applications and web page scripting.
... this introduction is the first in a series of articles on venkman and javascript debugging.
...And 42 more matches

Web Replay
devtools' debugger and console can be used to inspect and control the replay.
... an easy way to see this is to open the debugger developer tool, press the pause button and then the rewind button.
... time travel features this section describes extensions to the developer tools that use time travel to help debug a recording/replaying tab.
...And 37 more matches

Index - Archive of obsolete content
192 javascript debugger service code snippets no summary!
... 374 automatically handle failed asserts in debug builds as of 2004-12-8, it is now possible to automatically handle failed asserts in debug builds of mozilla for windows.
... 626 remote debugging when a bug is reproducible by a community member, but not on a developer's computer, a last-resort strategy is to debug it on the community member's computer.
...And 31 more matches

Index - Web APIs
654 console api api, debugging, overview, console, dump, log, output, test the console api provides functionality to allow developers to perform debugging tasks, such as logging messages or the values of variables at set points in your code, or timing how long an operation takes to complete.
... 4257 in depth: microtasks and the javascript runtime environment api, advanced, guide, javascript, microtasks, asynchronous, queuemicrotask, runtime when debugging or, possibly, when trying to decide upon the best approach to solving a problem around timing and scheduling of tasks and microtasks, there are things about how the javascript runtime operates under the hood that may be useful to understand.
... 4563 webgl_debug_renderer_info api, reference, webgl, webgl extension the webgl_debug_renderer_info extension is part of the webgl api and exposes two constants with information about the graphics driver for debugging purposes.
...And 31 more matches

MCD, Mission Control Desktop, AKA AutoConfig - Archive of obsolete content
create an email account, and configure imap and smtp: [root@calaz /usr/lib/thunderbird] $ cat thunderbird.cfg //put everything in a try/catch try { // 1) env variables if(getenv("user") != "") { // *nix settings var env_user = getenv("user"); var env_home = getenv("home"); } else { // windows settings var env_user = getenv("username"); var env_home = getenv("homepath"); } var env_mozdebug= getenv("mozilla_debug"); // var env_user = prompt("indiquez votre login", toto); // 2) lock general preferences //ldap address book lockpref("ldap_2.prefs_migrated", true); lockpref("ldap_2.servers.ldapint.auth.savepassword", true); lockpref("ldap_2.servers.ldapint.description", "ldap int"); lockpref("ldap_2.servers.ldapint.filename", "abook-1.mab"); lockpref("ldap_2.servers.ldapint.uri", "ldap...
...lockpref("mail.identity.id1.useremail", mail); lockpref("mail.server.server2.name", mail); lockpref("mail.identity.id1.fullname", cn); //debug with popup error messages doesn't work anymore :-( !!
... var env_mozdebug= getenv("mozilla_debug"); if (env_mozdebug) {displayerror("no error, just a debug, cn =" + cn + " and mail = " + mail); } } } // 4) call ldap servers to get ldap attributes (mail & cn), this will finally call processldapvalues, "3)" just above.
...And 30 more matches

dev/panel - Archive of obsolete content
note that at the moment you can't debug remote targets (for example, firefox os, the firefox os simulator, or firefox for android) using tools developed with this api.
...individual built-in tools, such as the javascript debugger or the web console, occupy "panels" in the toolbox.
...when the panel's created, the framework passes it a debuggee: this is a messageport object that you can use to exchange json messages with the browser that the developer tools are currently debugging.
...And 21 more matches

Tutorial: Set a breakpoint - Firefox Developer Tools
this page shows how you can try out the debugger api yourself using firefox’s scratchpad.
... we use debugger to set a breakpoint in a function, and then evaluate an expression whenever it is hit.
... since the debugger api is only available to privileged javascript code, you’ll need to use the browser content toolbox to try it out.
...And 20 more matches

How to get a stacktrace with WinDbg
(to get a stacktrace for thunderbird or some other product, substitute the product name where ever you see firefox in this instructions.) requirements to get such a stacktrace you need to install the following software: debugging tools for windows microsoft distributes the debugging tools for windows for free, those include windbg which you will need here.
... download it from install debugging tools for windows.
... debugging to begin debugging, ensure that firefox is not already running and open windbg from the start menu.
...And 17 more matches

Hacking Tips
it is separated in 2 parts, one section related to debugging and another section related to drafting optimizations.
... many of these tips only apply to debug builds of the js shell; they will not function in a release build.
... debugging tips getting help (from js shell) use the help function to get the list of all primitive functions of the shell with their description.
...And 16 more matches

WebReplayRoadmap
the low level, yet flexible architecture (described here) provides an extremely powerful platform for implementing debugging and analysis features.
... we would like to use web replay to radically improve not just the debugging experience but the entire web development experience.
... retroactive console logging console logging is one of the primary tools most developers use to debug a page.
...And 12 more matches

Web Console remoting - Firefox Developer Tools
for communication between the server and the client we use the remote debugging protocol.
... to better understand the architecture of the web console we recommend learning about the debugger architecture.
... to see how the debugger is used in the web console code, look in browser/devtools/webconsole/webconsole.js, and search for webconsoleconnectionproxy.
...And 12 more matches

Setting up an extension development environment - Archive of obsolete content
development preferences there is a set of development preferences that, when enabled, allows you to view more information about application activity, thus making debugging easier.
... nglayout.debug.disable_xul_cache = true.
... devtools.debugger.remote-enabled = true.
...And 11 more matches

Tamarin build documentation - Archive of obsolete content
note that additional command-line arguments are only available in the debug configuration.
... the tamarin codebase has the ability to build additional code which supports debugging hooks.
... in the xcode project, this is the debug_debugger and release_debugger configurations.
...And 11 more matches

Leak-hunting strategies and tips
hs leak gauge windows, documents, and docshells only all platforms any build gc and cc logs js objects, dom objects, many other kinds of objects all platforms any build leak tools for medium-size object graphs bloatview, refcount tracing and balancing objects that implement nsisupports or use moz_count_{ctor,dtor} all tier 1 platforms debug build (or build opt with --enable-logrefcnt) leaksoup (part of tracemalloc) all objects?
... mac any build leak tools for debugging memory growth that is cleaned up on shutdown diffbloatdump (part of tracemalloc) all allocations linux only?
...(but we have many virtual destructors in the codebase that don't need to be -- don't do that.) debugging leaks that go through xpconnect many large object graphs that leak go through xpconnect.
...And 11 more matches

NSS environment variables
3.12.3 nss_debug_pkcs11_module string (module name) name the pkcs#11 module to be traced.
... if set to to "1" or unset, softoken will trigger an assertion failure in debug builds, and will report an error in non-debug builds.
... if set to any other non-empty value, softoken will report an error in both debug and non-debug builds.
...And 11 more matches

Shell global objects
options is an optional object that may have these properties: isrunonce use the isrunonce compiler option (default: false) noscriptrval use the no-script-rval compiler option (default: false) filename filename for error messages and debug info linenumber starting line number for error messages and debug info columnnumber starting column number for error messages and debug info global global in which to execute the code newcontext if true, create and use a new cx (default: false) catchtermination if true, catch termination (failure without an exception value, as for slow scripts or out-of-memory) and return 'ter...
...this is what debugger.source.prototype.elementattributename returns.
...if present, options may have properties saying how the code should be compiled: noscriptrval use the no-script-rval compiler option (default: false) filename filename for error messages and debug info linenumber starting line number for error messages and debug info columnnumber starting column number for error messages and debug info element if present with value v, convert v to an object o and mark the source as being attached to the dom element o.
...And 11 more matches

UI Tour - Firefox Developer Tools
this article is a quick tour of the main sections of the javascript debugger's user interface.
... the ui is split vertically into three panels source list pane source pane the contents of the third pane depend on the current state of the debugger and may include the following sections: toolbar watch expressions breakpoints call stack scopes xhr breakpoints event listener breakpoints dom mutation breakpoints source list pane the source list pane lists all the javascript source files loaded into the page, and enables you to select one to debug.
... ignore source causes the debugger to skip the file when "stepping into" functions; this can be helpful for avoiding stepping into libraries used by your code.
...And 10 more matches

Venkman - Archive of obsolete content
venkman is the code name for mozilla's javascript debugger.
... it aims to provide a powerful javascript debugging environment for mozilla based browsers namely firefox, netscape 7.x/9.x and seamonkey.
... documentation venkman introduction an overview and some practical examples of using the javascript debugger in web development.
...And 9 more matches

Configuring Build Options
for example, a mozconfig-dbg: mk_add_options moz_objdir=@topsrcdir@/obj-ff-dbg ac_add_options --enable-debug and a mozconfig-rel-opt: mk_add_options moz_objdir=@topsrcdir@/obj-ff-rel-opt ac_add_options --disable-debug ac_add_options --enable-optimize allow for building both versions by specifiying the configuration via the mozconfig environment variable: $ env mozconfig=/path/to/mozconfig-dbg ./mach build $ env mozconfig=/path/to/mozconfig-rel-opt ./mach build don't forget to set the mozconfig env...
...if you want to use the build regularly, you will want a release build without extra debugging information; if you are a developer who wants to hack the source code, you probably want a non-optimized build with extra debugging macros.
... ac_add_options --enable-debug enables assertions in c++ and javascript, plus other debug-only code.
...And 9 more matches

Eclipse CDT
it also used to be necessary to add the following two lines to your mozconfig to make the compiler output errors all on a single line, but that may not be needed anymore: export cflags="-fmessage-length=0" export cppflags="-fmessage-length=0" debugging to create a debug configuration, open the project properties window, and select "run/debug settings" on the left.
...in the window that opens enter the path to your firefox binary (something like {your-obj-dir}/dist/nightlydebug.app/contents/macos/firefox) and select "disable auto build".
...isn't library_path for compile time, not runtime, linking?) in the workspace preferences, you may want to go to "c/c++ > debug > gdb" and deselect "stop on startup at", so that eclipse won't automatically break in main() when it launches firefox for debugging.
...And 9 more matches

Chapter 6: Firefox extensions and XUL applications - Archive of obsolete content
venkman, the javascript debugger venkman is a full-fledged javascript debugger that runs inside firefox.
... it works like typical debuggers, and is useful not only for developing extensions, but also for general web development.
... also, because it works with the javascript in extensions and firefox itself, the debugger can be a good way to learn about design methods.
...And 8 more matches

Using Breakpoints in Venkman - Archive of obsolete content
one of the basic tasks of debugging any language is setting breakpoints.
...when you set a breakpoint in a debugging application such as venkman, you can take advantage of the suspension to examine variables, objects, and other featues of the execution.
...basic breakpoints the stop button and debugger keyword are useful features of the javascript debugger, but when you are debugging deep in code—especially code you have authored yourself and are responsible for troubleshooting—you're going to need breakpoints.
...And 8 more matches

MMgc - Archive of obsolete content
poisoned memory in debug builds, mmgc writes "poison" into deallocated memory as a debugging aid.
...// before sweeping we check for missing write barriers bool gc::incrementalvalidation = false; // check for missing write barriers at every alloc bool gc::incrementalvalidationpedantic = false; if you suspect you have missing write barriers, turn these switches on in a debug build.
... (the second switch will slow your application down a lot more than the first switch, so you could try the first, then the second.) when a missing write barrier is detected, mmgc will assert and drop you into the debugger, and will print out a message telling you which object contained the missing write barrier, the address of the member variable that needs it, and what object didn't get marked due to the missing write barrier.
...And 7 more matches

Table Layout Regression Tests - Archive of obsolete content
while the information on the layout debugger is still useful, the testing information is much less relevant now than it has been, as the "rtest" testing framework described here has been superseded by the reftest framework.
... prerequisites in order to run these tests, you will need to have: make sure that your build is a debug build (in short you need ac_add_options --enable-debug in your .mozconfig file).
... to build the layoutdebugger itself, build either all extensions or include layoutdebug in your .mozconfig file.
...And 7 more matches

What are browser developer tools? - Learn web development
very useful for debugging and testing.
... find out more find more out about the inspector in different browsers: firefox page inspector ie dom explorer chrome dom inspector (opera's inspector works the same as this) safari dom inspector and style explorer the javascript debugger the javascript debugger allows you to watch the value of variables and set breakpoints, places in your code that you want to pause execution and identify the problems that prevent your code from executing properly.
... to get to the debugger: firefox: select ➤ web developer ➤ debugger or press ctrl + shift + s to open the javascript debugger.
...And 7 more matches

Capturing a minidump
this page describes how to capture these minidumps on windows, to permit better debugging.
... install debugging tools for windows microsoft distributes the debugging tools for windows for free, those include windbg which you will need here.
... download it from install debugging tools for windows.
...And 7 more matches

Tutorial: Show Allocations Per Call Path - Firefox Developer Tools
tutorial: show allocations per call path this page shows how to use the debugger api to show how many objects a web page allocates, sorted by the function call path that allocated them.
...(this menu will not be present unless you have changed the preference as explained above.) selecting the 'browser' context in the scratchpad enter the following code in the scratchpad: // this simply defines the 'debugger' constructor in this // scratchpad; it doesn't actually start debugging anything.
... components.utils.import('resource://gre/modules/jsdebugger.jsm'); adddebuggertoglobal(window); (function () { // the debugger we'll use to observe a tab's allocation.
...And 7 more matches

Migrate apps from Internet Explorer to Mozilla - Archive of obsolete content
<script> document.write("<script type='text\/javascript'>alert('hello');</" + "script>") </script> debug javascript mozilla provides several ways to debug javascript-related issues found in applications created for internet explorer.
...javascript console evaluating mozilla's javascript engine has built-in support for debugging, and thus can provide powerful tools for javascript developers.
... venkman, shown in figure 3, is a powerful, cross-platform javascript debugger that integrates with mozilla.
...And 6 more matches

Build instructions
(for posix shells), variable=value; export variable gmake target1 target2 here are some (not all) of the make variables that affect nss builds: build_opt: if set to 1, means do optimized non-debug build.
... default is debug, non-optimized build.
... use_debug_rtl: if set to 1, on windows, causes build with debug version of the c run-time library.
...And 6 more matches

Bytecode Descriptions
this is useful for the debugger and abstractgeneratorobject::isafteryieldorawait.
... debugleavelexicalenv no-op instruction that indicates leaving an optimized lexical scope.
...however, the debugger still needs to be notified when control exits a scope; that's what this instruction does.
...And 6 more matches

Using the Mozilla symbol server
this allows debugging of those builds without forcing all users to download large debugging files.
... note that because mozilla release builds are heavily optimized, debugging is not always easy.
... the debugger will not be able to show you the content of all variables and the execution path can seem strange because of inlining, tail calls, and other compiler optimizations.
...And 6 more matches

DevTools API - Firefox Developer Tools
while this api is currently a work-in-progress, there are usable portions of page inspector and debugger that may be used currently.
...a toolbox (and all the tools it contains) is linked to a target, which is the object the tools are debugging.
... parameters: target {target} - the target the toolbox will debug.
...And 6 more matches

Index - Learn web development
troubleshooting javascript article, beginner, codingscripting, debugging, developer tools, error, javascript, learn, tutorial, console.log, l10n:priority so there we have it, the basics of figuring out errors in simple javascript programs.
... 102 learn to style html using css beginner, css, codingscripting, debugging, landing, style, topic, length, specificity cascading stylesheets — or css — is the first technology you should start learning after html.
...this module looks at the cascade and inheritance, all the selector types we have available, units, sizing, styling backgrounds and borders, debugging, and lots more.
...And 5 more matches

Handling common JavaScript problems - Learn web development
browser developer tools browser developer tools have many useful features for helping to debug javascript.
... using the javascript debugger unfortunately, we still have the same error — the problem has not gone away.
... let's investigate this now, using a more sophisticated feature of browser developer tools: the javascript debugger as it is called in firefox.
...And 5 more matches

Command line options
-jsdebugger start application with browser toolbox (formerly browser debugger).
... that is different to venkman debugger (see option -venkman).
... -start-debugger-server port firefox only.
...And 5 more matches

Logging
nspr uses this facility itself for its own development debugging purposes.
... nspr also provides "assert"-style macros and functions to aid in application debugging.
...logging is compiled into the nspr debug builds; logging is not compiled into the nspr optimized builds.
...And 5 more matches

Index
211 nss tools ssltap the ssl debugging tool is an ssl-aware command-line proxy.
... -v enable debug logging when importing.
...retaining the temporary directories can be an aid to debugging.
...And 5 more matches

NSS API Guidelines
use #ifdef debug to include the array in debug builds only.
... the advantage of using an array is that you can use strings(1) to pull the id tags out of a (debug) compiled library.
... here is an example from lib/base/baset.h: #ifdef debug static const char baset_cvs_id[] = "@(#) $rcsfile: nss-guidelines.html, v $ $revision: 48936 $ $date: 2009-08-11 07:45:57 -0700 (tue, 11 aug 2009) $ $name$"; #endif /* debug */ the difference, between this and id, is that id has some useless information (every file is "experimental"), and doesn't have name.
...And 5 more matches

SpiderMonkey Build Documentation
(if you want to use spidermonkey as a library in your c++ application, or work on improving spidermonkey itself, do a developer/debug build instead, as described below.) cd js/src # this name should end with "_opt.obj" to make the version control system ignore it.
... developer (debug) build for developing and debugging spidermonkey itself, it is best to have both a debug build (for everyday debugging) and an optimized build (for performance testing), in separate build directories.
... thus, in addition to following the steps above, you should also create a debug build using these steps: cd js/src # this name should end with "_dbg.obj" to make the version control system ignore it.
...And 5 more matches

nsIXPConnect
nsistackframe createstackframelocation(in pruint32 alanguage, in string afilename, in string afunctionname, in print32 alinenumber, in nsistackframe acaller); void debugdump(in short depth); void debugdumpevalinjsstackframe(in pruint32 aframenumber, in string asourcetext); void debugdumpjsstack(in prbool showargs, in prbool showlocals, in prbool showthisprops); void debugdumpobject(in nsisupports acomobj, in short depth); [noscript,notxpcom] prbool definedomquickstubs(in jscontextptr cx, in jsobjectptr proto, in pruint32 flags,...
...jectptr anewscope); obsolete since gecko 1.9.1 nsixpconnectjsobjectholder reparentwrappednativeiffound(in jscontextptr ajscontext, in jsobjectptr ascope, in jsobjectptr anewparent, in nsisupports acomobj); void restorewrappednativeprototype(in jscontextptr ajscontext, in jsobjectptr ascope, in nsiclassinfo aclassinfo, in nsixpconnectjsobjectholder aprototype); void setdebugmodewhenpossible(in prbool mode); native code only!
...nt32 alanguage, in string afilename, in string afunctionname, in print32 alinenumber, in nsistackframe acaller ); parameters alanguage missing description afilename missing description afunctionname missing description alinenumber missing description acaller missing description return value missing description exceptions thrown missing exception missing description debugdump() void debugdump( in short depth ); parameters depth missing description exceptions thrown missing exception missing description debugdumpevalinjsstackframe() void debugdumpevalinjsstackframe( in pruint32 aframenumber, in string asourcetext ); parameters aframenumber missing description asourcetext missing description exceptions thrown missing exception mis...
...And 5 more matches

Browser Toolbox - Firefox Developer Tools
the browser toolbox enables you to debug add-ons and the browser's own javascript code rather than just web pages like the normal toolbox.
... note: if you want to debug a specific add-on that is restartless or sdk-based then try the add-on debugger.
... to enable it you need to check the settings "enable chrome and addon debugging" and "enable remote debugging".
...And 5 more matches

Chapter 5: Let's build a Firefox extension - Archive of obsolete content
preference description value nglayout.debug.disable_xul_cache (not present in firefox 3.5+) ordinarily, firefox will cache xul documents after they have been read in once, to speed subsequent displays.
... true browser.dom.window.dump.enabled (not present in firefox 3.5+) enables use of the dump method for debugging.
... refer to the “javascript debugging methods” sidebar.
...And 4 more matches

Unix stub installer - Archive of obsolete content
the unix stub installer project resides at: <http://lxr.mozilla.org/seamonkey/sou...ard/unix/src2/> how do we get setup to debug the unix stub installer?
... build the unix installer (debug or non-debug target) by typing "make" in the src2 directory grab a nightly build, say from <http://ftp.mozilla.org/pub/mozilla/n...staller.tar.gz> gunzip and untar the build to some temporary location like /tmp.
...copy the xpi directory into the src2 directory you are debugging from.
...And 4 more matches

Eclipse CDT Manual Setup
select "run/debug > console" and deselect "limit console output".
...eclipse still indexes it without this filter!) if you have secondary object directories (object directories that are not your only/the primary object directory) for the source tree and those directories are inside the source tree (or if you might have such object directories in future), then add an "exclude all", regular expression filter for folders with a project relative path matching "obj(?!-debug(?:$|/)).+".
... this particular regular expression will exclude all directories beginning with the string "obj" except "obj-debug", so if "obj-debug" is not the name of your main object directory, then adjust the regular expression as necessary.
...And 4 more matches

Gecko Logging
error 1 an error occurred, generally something you would consider asserting in a debug build.
... debug 4 a debug message, useful for debugging but too verbose to be turned on normally.
... verbose 5 a message that will be printed a lot, useful for debugging program flow and will probably impact performance.
...And 4 more matches

Use watchpoints - Firefox Developer Tools
when debugging javascript code, it can be useful to know when properties on objects are read or modified.
...in the firefox debugger, this information can be provided by watchpoints.
... set a watchpoint run and then pause the debugger.
...And 4 more matches

Appendix D: Loading Scripts - Archive of obsolete content
debuggable: development tools support debugging javascript loaded by script tags disadvantages scoping: scripts loaded via script tags share the global scope with all other scripts loaded into the same window.
...this information is invaluable for debugging, and the flexibility with which it can be specified makes this method useful for extracting javascript from a number of file formats other than raw javascript scripts.
...some known issues include: e4x xml objects cannot be wrapped for passage between compartments: bug 613142 there are a number of type detection issues, including: string.replace does not recognize regexp objects from foreign compartments: bug 633830 debugging: support for sandbox evaluation in development tools is uneven.
...And 3 more matches

Setting Up a Development Environment - Archive of obsolete content
once you're testing and debugging your code, you'll find that constantly building and installing an xpi can be very tedious.
... javascript debugger the name says it all.
... the venkman javascript debugger is a great way to trace execution of your javascript code.
...And 3 more matches

Mac stub installer - Archive of obsolete content
the mac stub installer project resides at: <http://lxr.mozilla.org/seamonkey/sou...ll/wizard/mac/> the mac stub installer source code resides at: <http://lxr.mozilla.org/seamonkey/sou...izard/mac/src/> how do we get setup to debug the mac installer?
... build the mac installer (debug or non-debug target) using miw.mcp grab a nightly build, say from <http://ftp.mozilla.org/pub/mozilla/n...taller.sea.bin> drop in the installer binary next to the "mozilla installer" in the "mozilla installer" folder created by unstuffing the opt build.
... alternative to steps 3 and 4 copy the "installer modules" folder from the "mozilla installer" folder into the "macbuild" folder that contains the build debug or non-debug installer binary next to miw.mcp.
...And 3 more matches

Template Logging - Archive of obsolete content
« previous debugging problems with a template can be difficult as many problems are logic errors that are often not possible to determine automatically.
...fortunately, some debugging and logging support is provided with templates that may help.
...the first debugging method involves logging all new results that apply to the template due to the data changing as well as logging results that are changed or removed.
...And 3 more matches

Profiling with the Firefox Profiler
for local builds of fennec, you should build with optimization and strip_flags="--strip-debug" but not with --enable-profiling.
... set devtools.debugger.remote-enabled to true in about:config for fennec.
...if you want 90mb use 10000000, and 20000000 for 180mb, which are good values to debug long startups.
...And 3 more matches

NSPR build instructions
build the libraries build the test programs for example, # check out the source tree from mercurial hg clone https://hg.mozilla.org/projects/nspr # create a build directory mkdir target.debug cd target.debug # run the configure script ../nspr/configure [optional configure options] # build the libraries gmake # build the test programs cd pr/tests gmake on mac os x, use make, which is gnu make.
... nspr build generates a debug build by default.
... --disable-debug --enable-optimize specify these two options to generate an optimized (release) build.
...And 3 more matches

SpiderMonkey Internals
there is an additional public api for javascript debuggers, jsdbgapi, but js/jsd/jsdebug.h might be a better api for debuggers.
... jsdbgapi.cpp, jsdbgapi.h the debugging api.
...the debugger will have to consult jsopcode.def on its own to figure out where to plant trap instructions to implement functions like step out, but a future jsdbgapi.h will provide convenience interfaces to do these things.
...And 3 more matches

Index
is was removed in bug 1127201 144 ns_addref xpcom, xpcom_macros macro 145 ns_assertion xpcom, xpcom_macros macro 146 ns_ensure_arg_pointer xpcom, xpcom_macros macro 147 ns_error xpcom, xpcom_macros throws a assertion (ns_assertion) with the text "error: (error text)", so writes this text to console (stderr) and to debug logs (nspr logging).
... 176 ijsdebugger debugger, interfaces, interfaces:scriptable, xpcom interface reference implemented by: @mozilla.org/jsdebugger;1 as a service: 177 amiinstallcallback interfaces, interfaces:scriptable, xpcom, xpcom interface reference called when an install completes or fails.
...see the version_* consts on jsdidebuggerservice.
...And 3 more matches

nsIEventListenerInfo
1.0 66 introduced gecko 1.9.2 inherits from: nsisupports last changed in gecko 1.9.2 (firefox 3.6 / thunderbird 3.1 / fennec 1.0) method overview nsisupports getdebugobject(); astring tosource(); attributes attribute type description allowsuntrusted boolean indicates whether or not the event listener allows untrusted events.
... methods getdebugobject() returns the debugger object if the debug service is active.
... nsisupports getdebugobject(); parameters none.
...And 3 more matches

Reference Manual
in debug builds, if you subvert this invariant with one of the assignment forms that doesn't call queryinterface, nscomptr will assert at runtime in the bad assignment.
...implementation details and debugging machinery although it is a class, nscomptr has no virtual methods, and therefore, no vtable or vptr.
... because a few key routines are factored out into a common non-template base class, the actual underlying pointer is stored as an nsisupports* (except in debug builds where nscap_feature_debug_ptr_types is turned on).
...And 3 more matches

Mozilla
benchmarking debug builds (--enable-debug) and non-optimized builds (--disable-optimize) are much slower.
... debugging debugging a project as large as mozilla can be a daunting task.
... fortunately, over the years, mozilla developers have come up with not just technologies and features to help you debug code, but have devised tips and techniques that can help too.
...And 3 more matches

Examine, modify, and watch variables - Firefox Developer Tools
this feature isn't yet supported in the new debugger.
... if you need to use it, you can, for now, switch back to the old debugger by visiting about:config and setting the "devtools.debugger.new-debugger-frontend" preference to false.
... to see the docs for the old debugger, please visit debugger (before firefox 52).
...And 3 more matches

Migrating from Firebug - Firefox Developer Tools
the network monitor can be opened via ctrl+shift+q / cmd+opt+q, the web console via ctrl+shift+k / cmd+opt+k and the debugger via ctrl+shift+s / cmd+opt+s.
...to stop the script execution there, you need to set a breakpoint on the line with the modification within the debugger panel.
... debugger what's the script panel in firebug, is the debugger panel in the devtools.
...And 3 more matches

Settings - Firefox Developer Tools
debugger enable source maps enable source map support in the debugger.
... enable new debugger frontend enable the new debugger.
... enable browser chrome and add-on debugging toolboxes enable you to use developer tools in the context of the browser itself, and not only web content.
...And 3 more matches

Firefox Developer Tools
you can use them to examine, edit, and debug html, css, and javascript.
... this section contains detailed guides to all of the tools as well as information on how to debug firefox for android, how to extend devtools, and how to debug the browser as a whole.
... javascript debugger stop, step through, examine, and modify the javascript running in a page.
...And 3 more matches

Developing for Firefox Mobile - Archive of obsolete content
we'll use the android debug bridge (adb) to communicate between the add-on sdk and the device.
... enable usb debugging on the device (step 2 of this link only) on the development machine: install version 1.5 or higher of the add-on sdk install the correct version of the android sdk for your device using the android sdk, install the android platform tools next, attach the device to the development machine via usb.
... this will be followed by lots of debug output.
...And 2 more matches

Using microformats - Archive of obsolete content
debug specify true if debug mode is in use; otherwise, specify false.
... debug() returns a string that describes a microformat object.
... note: you can simply call debug() on a microformat object: microformatobject.debug() instead of using this method if you prefer.
...And 2 more matches

Running Tamarin acceptance tests - Archive of obsolete content
reason: inconsistencies in different debug output, need to implement regex matching of diffs 2527 running abcasm/branchtocommon.abs 2530 running abcasm/arithmetic.abs 2529 running abcasm/bkpt.abs 2528 running abcasm/bkptline.abs 2526 running abcasm/bug_476556.abs 2524 running abcasm/bug_491056.abs ...
... for each test run regardless of results, then print the test run summary when finished --ascargs= : additional arguments to pass to asc.jar --vmargs= : additional arguments to pass to avmshell --random : run tests in random order --timeout : max time for testrun --verify : run a verify pass instead of running abcs --verifyonly : run a -dverifyonly pass: only checks test exitcode (only works with debugger vms) testing the android shell the instructions above apply to running tests on an android device as well, but with a few differences.
...adb 'adb' stands for android debug bridge.
...And 2 more matches

Using gdb on wimpy computers - Archive of obsolete content
the debugger uses a lot of memory.
...if you don't allow those libraries to be loaded then gdb will not be able to properly debug threads on linux.
...a]$ cd dist/bin/ [blizzard@gunhead bin]$ ./mozilla -g .//run-mozilla.sh -g ./mozilla-bin mozilla_five_home=/home/blizzard/src/mozilla/mozilla/dist/bin ld_library_path=/home/blizzard/src/mozilla/mozilla/dist/bin shlib_path=/home/blizzard/src/mozilla/mozilla/dist/bin libpath=/home/blizzard/src/mozilla/mozilla/dist/bin moz_program=./mozilla-bin moz_toolkit= moz_debug=1 moz_debugger= /usr/bin/gdb ./mozilla-bin -x /tmp/mozargs22288 gnu gdb 19991004 copyright 1998 free software foundation, inc.
...And 2 more matches

Tamarin Tracing Build Documentation - Archive of obsolete content
note that additional command-line arguments are only available in the debug configuration.
...the tamarin codebase has the ability to build additional code which supports debugging hooks.
... in the xcode project, this is the debug_debugger and release_debugger configurations.
...And 2 more matches

HTTP logging
sometimes, while debugging your web app (or client-side code using necko), it can be useful to log http traffic.
... thanks for helping us debug firefox.
... export moz_log=timestamp,rotate:200,nshttp:5,cache2:5,nssockettransport:5,nshostresolver:5,cookie:5 export moz_log_file=/tmp/log.txt cd /path/to/firefox ./firefox reproduce the problem you're debugging.
...And 2 more matches

Log.jsm
// use dots to create a hierarchy, this way you can later change // the log level of sets of loggers under some common root let log = log.repository.getlogger("myextension.myclass"); log.level = log.level.debug; // a console appender logs to the browser console.
...something bad happened!"); log.debug("details about bad thing only useful during debugging", {someinfo: "nothing"}); log.warn("here is an error", new error("ouch")); logger levels fatal severe errors that cause premature termination.
... debug detailed information on the flow through the system.
...And 2 more matches

NSS_3.12_release_notes.html
both debug and optimized builds are provided.
... go to the subdirectory for your platform, dbg (debug) or opt (optimized), to get the tar.gz or zip file.
... bug 354403: nsslist_createiterator returns pointer to a freed memory if the function fails to allocate a lock bug 399236: pkix wrapper must print debug output into stderr bug 399300: pkix error results not freed after use.
...And 2 more matches

NSS Tools ssltap
using the ssl debugging tool (ssltap) newsgroup: mozilla.dev.tech.crypto the ssl debugging tool is an ssl-aware command-line proxy.
... syntax to run the ssl debugging tool, type this command in a command shell: ssltap [-vhfsxl] [-p port] hostname:port options the command does not require any options other than hostname:port, but you normally use them to control the connection interception and output.
...the following are well-known port numbers: http 80 https 443 smtp 25 ftp 21 imap 143 imaps 993 (imap over ssl) nntp 119 nntps 563 (nntp over ssl) examples you can use the ssl debugging tool to intercept any connection information.
...And 2 more matches

Index
it is separated in 2 parts, one section related to debugging and another section related to drafting optimizations.
... many of these tips only apply to debug builds of the js shell; they will not function in a release build.
... 439 js_set_tracing_details jsapi reference, spidermonkey set debugging information about the next thing to be traced by a jstracer.
...And 2 more matches

Set watch expressions - Firefox Developer Tools
when debugging code, sometimes it's useful to watch expressions as executions are paused.
... the debugger features a pane for entering expressions to be watched (watch expressions).
... as you step through code, the debugger will watch the expression and return any results.
...And 2 more matches

Deprecated tools - Firefox Developer Tools
unlike in scratchpad, errors are properly displayed in the output with an expandable stacktrace, making it easier to debug the code you're currently writing.
... alternatives remote debugging is available in about:debugging as of firefox 68.
... features not ported to about:debugging are: wifi debugging for firefox for android, application development.
...And 2 more matches

Examine and edit HTML - Firefox Developer Tools
clicking the marker opens a tooltip listing the event listeners and allows you for each listener to switch to the line of javascript code in the debugger where the listener is defined.
...clicking the marker switches to the line of javascript code in the debugger where the custom element got defined.
... ::before and ::after you can inspect pseudo-elements added using ::before and ::after: custom element definition when you open the inspector on a page that includes custom elements, you can view the class definition for the custom element in the debugger: inspect the element click on the word custom the source for the element's class will be displayed in the debugger.
...And 2 more matches

JavaScript
it is a restricted variant of ecmascript 5, for faster performance and easier debugging.
... tools & resources helpful tools for writing and debugging your javascript code.
... firefox developer tools web console, javascript profiler, debugger, and more.
...And 2 more matches

console - Archive of obsolete content
console.debug(...) deprecated, you should use console.log() instead.
...especially when debug logging shows up in a production environment, the noise can make it harder, not easier, to debug issues.
... the complete set of logging levels is given in the table below, along with the set of functions that will result in output at each level: level will log calls to: all any console method debug debug(), error(), exception(), info(), log(), time(), timeend(), trace(), warn() info error(), exception(), info(), log(), time(), timeend(), trace(), warn() warn error(), exception(), warn() error error(), exception() off nothing setting the logging level the logging level defaults to "error".
...this means that messages written using debug(), log(), info(), trace(), and warn() will not appear in the console.

Index of archived content - Archive of obsolete content
ution dialogs and prompts downloading files drag & drop embedding svg examples and demos from articles file i/o finding window handles forms related code snippets html in xul for rich tooltips html to dom isdefaultnamespace js xpcom javascript debugger service javascript timers javascript daemons management label and description lookupnamespaceuri lookupprefix miscellaneous modules on page load page loading post data to window preferences progr...
...rs how mozilla finds its configuration files how thunderbird and firefox find their configuration files introduction kill the xul.mfl file for good locked config settings other mozilla customization pages protecting mozilla's registry.dat file automatically handle failed asserts in debug builds blackconnect blackwood bonsai bookmark keywords build building transformiix standalone chromeless compiling the npruntime sample plugin in visual studio creating a firefox sidebar extension creating a microsummary creating a mozilla extension add...
...gposts build bundlelibrary bundles configuration extensions faq hostwindow installer scripting styling proxy ui pydom rdf api rdf datasource how-to reading textual data remote xul remote debugging rsyncing the cvs repository running windows debug builds downloaded from tinderbox sxsw 2007 presentations safe browsing safe browsing: design documentation safely loading uris same origin policy for xbl space manager detailed design space manager high level design standalone xpcom st...
... xulrunner application update article building xulrunner building xulrunner with python commandline components creating xulrunner apps with the mozilla build system creating a windows inno setup installer for xulrunner applications custom app bundles for mac os x debugging a xulrunner application deploying xulrunner dialogs in xulrunner getting started with xulrunner how to enable locale switching in a xulrunner application macfaq make your xulrunner app match the system locale opening a link in the default browser specifying startup chrome window using c...

Nanojit - Archive of obsolete content
figuring out how to compile it is left as an exercise for the reader; the following works when run in the object directory of an --enable-debug spidermonkey shell: g++ -ddebug -g3 -wno-invalid-offsetof -fno-rtti -include js-confdefs.h -i dist/include/ -i..
... -i ../nanojit -o jittest ../jittest.cpp libjs_static.a note: remove the -ddebug if you have not compiled spidermonkey with --enable-debug, and use whatever you called the sample source file in place of jittest.cpp.
... #include <stdio.h> #include <stdint.h> #include "jsapi.h" #include "jstracer.h" #include "nanojit.h" using namespace nanojit; const uint32_t cache_size_log2 = 20; static avmplus::gc gc = avmplus::gc(); static avmplus::avmcore core = avmplus::avmcore(); int main() { logcontrol lc; #ifdef debug lc.lcbits = lc_readlir | lc_assembly; #else lc.lcbits = 0; #endif // set up the basic nanojit objects.
... allocator *alloc = new vmallocator(); codealloc *codealloc = new codealloc(); assembler *assm = new (&gc) assembler(*codealloc, *alloc, &core, &lc); fragmento *fragmento = new (&gc) fragmento(&core, &lc, cache_size_log2, codealloc); lirbuffer *buf = new (*alloc) lirbuffer(*alloc); #ifdef debug fragmento->labels = new (*alloc) labelmap(*alloc, &lc); buf->names = new (*alloc) lirnamemap(*alloc, fragmento->labels); #endif // create a fragment to hold some native code.

Venkman Internals - Archive of obsolete content
gijskruitbosch 05:41, 7 march 2007 (pst) venkman-debugger.js sets hooks in to the jsdidebuggerservice.
... initdebugger().
... scriptmanager in initdebugger() the previous loaded scripts are passed to an onscriptcreated() method which binds them to a scriptmanager.
... venkman-utils.js defines the dd debug dump and friends windowrecord representation of the open windows.

Getting started with XULRunner - Archive of obsolete content
here is mine: pref("toolkit.defaultchromeuri", "chrome://myapp/content/main.xul"); /* debugging prefs, disable these before you deploy your application!
... */ pref("browser.dom.window.dump.enabled", true); pref("javascript.options.showinconsole", true); pref("javascript.options.strict", true); pref("nglayout.debug.disable_xul_cache", true); pref("nglayout.debug.disable_xul_fastload", true); xulrunner specific preferences include: toolkit.defaultchromeuri specifies the default window to open when the application is launched.
... the debugging preferences are discussed in debugging a xulrunner application step 7: create some xul finally, we need to create a simple xul window, which is described in the file main.xul.
...from a windows command prompt opened to the myapp folder, we should be able to execute this: c:\path\to\xulrunner.exe application.ini of course, if you opted to install xulrunner then you could simply do ​%programfiles%\xulrunner.exe application.ini or on 64 bit systems ​%programfiles(x86)%\xulrunner.exe application.ini note: you can also install your application when you're finished debugging it.

Archived Mozilla and build documentation - Archive of obsolete content
automated testing tips and tricks automatic mozilla configurator ankh8 automatically handle failed asserts in debug builds as of 2004-12-8, it is now possible to automatically handle failed asserts in debug builds of mozilla for windows.
... venkman venkman is the code name for mozilla's javascript debugger.
... it aims to provide a powerful javascript debugging environment for mozilla based browsers namely firefox, netscape 7.x/9.x and seamonkey.
...a xul validator and the error console are both available to help debug problems.

Developing Mozilla XForms - Archive of obsolete content
debugging always start with a debug build of the xforms and the schema-validation extensions.
... see building mozilla xforms for a .mozconfig for debug builds.
... you should create a new, clean profile for debugging.
...to activate this logging output, set the nspr_log_modules environment variable: export nspr_log_modules=schemavalidation:5 this only works on a debug build as described above.

Obsolete Build Caveats and Tips
alternatively you can install the command-line compiler as part of the windows 7 sdk, but you are then expected to use the included windbg debugger.
... the visual c++ 8 command-line compiler is included with the vista sdk, but you are then expected to use the included windbg debugger.
...you only need to follow the steps below if you want to customize the build (e.g., to create a debug build or a release build with debug symbols), you want to build something other than firefox, or you want to build pre-gecko 5.0 source.
... if you are building mozilla source code from before firefox 5, then you must first select the mozilla application that you want to build (see below), and you will probably also need to set at least some of the other basic configuration options (such as whether to build a debug build or not) to get the type of build that you need.

Implementing QueryInterface
// ...but that won't matter when someone calls me wrongly in a non-debug build.
... it tests for bad input with an ns_assertion, to find logic errors immediately in debug builds.
...in general, i disapprove of macros except in cases where the macro must expand to different text in different situations, e.g., different platforms, debugging vs.
... non-debugging, et al.

nss tech note2
to enable the module logger, you must set the environment variable nss_debug_pkcs11_module to the name of the target module.
... for example, to log the softoken, use: nss_debug_pkcs11_module="nss internal pkcs #11 module" note: in the command prompt on windows, do not quote the name of the target module, otherwise the quotes are considered part of the name.
... for example, to log the softoken on windows, use: set nss_debug_pkcs11_module=nss internal pkcs #11 module the logger is available by default in debug builds.
... for optimized builds, nss must be built with the variable debug_pkcs11 set.

NSS tools : ssltab
name ssltap — tap into ssl connections and display the data going by synopsis libssltap [-vhfsxl] [-p port] [hostname:port] description the ssl debugging tool ssltap is an ssl-aware command-line proxy.
...the following are well-known port numbers: * http 80 * https 443 * smtp 25 * ftp 21 * imap 143 * imaps 993 (imap over ssl) * nntp 119 * nntps 563 (nntp over ssl) usage and examples you can use the ssl debugging tool to intercept any connection information.
...the simplest way to use the debugging tool is to execute the following command from a command shell: $ ssltap www.netscape.com the program waits for an incoming connection on the default port 1924.
...the browser retrieves the requested page from the server at www.netscape.com, but the page is intercepted and passed on to the browser by the debugging tool on intercept.

NSS tools : ssltap
name ssltap — tap into ssl connections and display the data going by synopsis libssltap [-vhfsxl] [-p port] [hostname:port] description the ssl debugging tool ssltap is an ssl-aware command-line proxy.
...the following are well-known port numbers: * http 80 * https 443 * smtp 25 * ftp 21 * imap 143 * imaps 993 (imap over ssl) * nntp 119 * nntps 563 (nntp over ssl) usage and examples you can use the ssl debugging tool to intercept any connection information.
...the simplest way to use the debugging tool is to execute the following command from a command shell: $ ssltap www.netscape.com the program waits for an incoming connection on the default port 1924.
...the browser retrieves the requested page from the server at www.netscape.com, but the page is intercepted and passed on to the browser by the debugging tool on intercept.

NSS_3.12.3_release_notes.html
both debug and optimized builds are provided.
... go to the subdirectory for your platform, dbg (debug) or opt (optimized), to get the tar.gz or zip file.
... if set to to "1" or unset, softoken will trigger an assertion failure in debug builds, and will report an error in non-debug builds.
... if set to any other non-empty value, softoken will report an error in both debug and non-debug builds.

NSS tools : ssltap
name ssltap — tap into ssl connections and display the data going by synopsis libssltap [-vhfsxl] [-p port] [hostname:port] description the ssl debugging tool ssltap is an ssl-aware command-line proxy.
... the following are well-known port numbers: * http 80 * https 443 * smtp 25 * ftp 21 * imap 143 * imaps 993 (imap over ssl) * nntp 119 * nntps 563 (nntp over ssl) usage and examples you can use the ssl debugging tool to intercept any connection information.
...the simplest way to use the debugging tool is to execute the following command from a command shell: $ ssltap www.netscape.com the program waits for an incoming connection on the default port 1924.
...the browser retrieves the requested page from the server at www.netscape.com, but the page is intercepted and passed on to the browser by the debugging tool on intercept.

Introduction to the JavaScript shell
gczeal(level) added in spidermonkey 1.8 debug only.
... set the level of gc zeal, a debugging feature.
... this is a powerful debugging mechanism when used in concert with line2pc().
... debug functions these built-in functions are only available in debug builds.

JS_NewGlobalObject
hookoption js::onnewglobalhookoption see debugger api hook added in spidermonkey 31 options const js::compartmentoptions &amp; the option for new compartment (passed to jscompartment constructor).
... debugger api hook during global creation, we fire notifications to callbacks registered via the debugger api.
... this api provides a way for consumers to set slots atomically (immediately after the global is created), before any debugger hooks are fired.
...this lets us be sure that debugger clients never miss breakpoints.

JS_SET_TRACING_DETAILS
this article covers features introduced in spidermonkey 1.8 set debugging information about the next thing to be traced by a jstracer.
... syntax js_set_tracing_details(trc, printer, arg, index) name type description trc jstracer * the tracer whose debugging hooks are to be set.
... description set debugging information about a reference to a traceable thing to prepare for the following call to js_calltracer.
...when printer is not null, the arg and index arguments are available to the callback as the debugprinterarg and debugprintindex fields of trc.

JS_SetGCZeal
this article covers features introduced in spidermonkey 1.8 enable gc zeal, a testing and debugging feature that helps find gc-related bugs in jsapi applications.
... with gc zeal enabled, gc-related crashes are much easier to reproduce (they happen more reliably) and debug (they happen sooner, closer to the source of the bug).
...this function is available only in debug builds.
...(in a debug build of gecko, you can also set the current gc zeal level using the javascript.options.gczeal preference.) see also mxr id search for js_setgczeal mxr id search for js_gc_zeal js_schedulegc bug 308429 bug 650978 ...

TPS Tests
note: if you are updating the tps environment and want to keep your existing config (eg, the existing username and password), you should instead execute: python create_venv.py --keep-config %path% activate the environment source %path%/bin/activate run some tests note that the testfile is not a path, it should only be the filename from services/sync/tests/tps/ runtps --debug --testfile %test_file_name% --binary %firefox_binary_path% additionally, omitting a --testfile parameter will cause it to run all tps tests listed in services/sync/tests/tps/all_tests.json an example on osx, for running just the test_sync.js testfile against a locally built firefox (where the mozconfig set the objdir to obj-ff-artifact): runtps --debug --testfile test_sync.j...
... for example, consider the first action in the phase above: [bookmarks.add, bookmarks_initial] you could rewrite this as a custom function so as to add some custom logging: [async () => { logger.loginfo("adding bookmarks_initial"); await bookmarks.add(bookmarks_initial); }] note that this is probably best used for debugging, and new tests that want custom behavior should add it to the tps addon so that other tests can use it.
... troubleshooting and debugging tips for writing and running tps tests tps evaluates the whole file in every phase, so any syntax error(s) in the file will get reported in phase 1, even though the error may not be in phase 1 itself.
... run runtps with --debug.

Thread Sanitizer
# note: the use of this flag causes clang to automatically link the tsan runtime :) export ldflags="-fsanitize=thread -fpic -pie" # these three are required by tsan ac_add_options --disable-jemalloc ac_add_options --disable-crashreporter ac_add_options --disable-elf-hack # keep symbols to symbolize tsan traces export moz_debug_symbols=1 ac_add_options --enable-debug-symbols ac_add_options --disable-install-strip # settings for an opt build ac_add_options --enable-optimize="-o2 -gline-tables-only" ac_add_options --disable-debug starting the build process now you start the build process using the regular make -f client.mk command.
... $0 <dirname>" elif [ -d $1 ] ; then echo "directory $1 already exists" else autoconf2.13 mkdir $1 cd $1 llvm_root="/path/to/llvm" cc="$llvm_root/build/bin/clang" \ cxx="$llvm_root/build/bin/clang++" \ cflags="-fsanitize=thread -fpic -pie" \ cxxflags="-fsanitize=thread -fpic -pie" \ ldflags="-fsanitize=thread -fpic -pie" \ ../configure --disable-debug --enable-optimize="-o2 -gline-tables-only" --enable-llvm-hacks --disable-jemalloc make -j 8 fi using llvm symbolizer for faster/better traces by default, tsan traces are symbolized because otherwise, the runtime suppression list wouldn't work.
...furthermore, additional debug information is included in traces when llvm-symbolizer is used.
...this list is a good tool to temporarily hide some traces, especially for debugging purposes.

Ignore a source - Firefox Developer Tools
however, a library’s abstraction leaks during debugging sessions when you are forced to step through its stack frames in order to reach your own code.
... however, you can tell the debugger to ignore the details of selected sources.
... when “pause on exceptions” is enabled in the debugger settings, the debugger won’t pause when an exception is thrown in the ignored source; instead it waits until (and if) the stack unwinds to a frame in a source that isn’t ignored.
... the debugger skips through ignored sources when stepping.

Use a source map - Firefox Developer Tools
in these situations, it's much easier to debug the original source, rather than the source in the transformed state that the browser has downloaded.
... a source map is a file that maps from the transformed source to the original source, enabling the browser to reconstruct the original source and present the reconstructed original in the debugger.
... to enable the debugger to work with a source map, you must: generate the source map include a comment in the transformed file, that points to the source map.
...the compiled source contains a comment like this, that points to a source map: //# sourcemappingurl=main.js.map in the debugger's source list pane, the original coffeescript source now appears as "main.coffee", and we can debug it just like any other source.

Using the WebAssembly JavaScript API - WebAssembly
the equivalent code would look like this: fetch('simple.wasm').then(response => response.arraybuffer() ).then(bytes => webassembly.instantiate(bytes, importobject) ).then(results => { results.instance.exports.exported_func(); }); viewing wasm in developer tools in firefox 54+, the developer tool debugger panel has functionality to expose the text representation of any wasm code included in a web page.
... to view it, you can go to the debugger panel and click on the “wasm://” entry.
... starting soon in firefox, in addition to viewing webassembly as text, developers will be able to debug (place breakpoints, inspect the callstack, single-step, etc.) webassembly using the text format.
... see webassembly debugging with firefox devtools for a video preview.

cfx - Archive of obsolete content
this enables you to run your add-on alongside debuggers like firebug.
... for example, if you type: cfx run ---no-run you will see something like: to launch the application, enter the following command: /path/to/firefox/firefox-bin -profile /path/to/profile/tmpjdnlp6.mozrunner -foreground -no-remote this enables you to run the add-on without going through cfx, which might be useful if you want to run it inside a debugger like gdb.
... for example, if you type: cfx run ---no-run you will see something like: to launch the application, enter the following command: /path/to/firefox/firefox-bin -profile /path/to/profile/tmpjdnlp6.mozrunner -foreground -no-remote this enables you to run the add-on without going through cfx, which might be useful if you want to run it inside a debugger like gdb.

jpm - Archive of obsolete content
for example, to pass the -jsconsole argument to firefox and launch the browser console, try the following: jpm run --binary-args -jsconsole to pass multiple arguments, or arguments containing spaces, quote them: jpm run --binary-args '-url mzl.la -jsconsole' --debug run the add-on debugger attached to the add-on.
... for example, to pass the -jsconsole argument to firefox, which will launch the browser console, try the following: jpm test --binary-args -jsconsole to pass multiple arguments, or arguments containing spaces, quote them: jpm test --binary-args '-url mzl.la -jsconsole' --debug run the add-on debugger attached to the add-on.
...see the debugging section if you are experiencing difficulty installing a signed add-on.

Local Storage - Archive of obsolete content
we recommend that you at least keep an error log, so that you can request error data from your users when you encounter problems that are hard to debug.
...any extension that is more complex than a hello world needs some way to log errors and trace execution without having to fire up a debugger.
... and then logging is done with any of the following methods, depending on the kind of message being logged: this._logger.fatal("this is a fatal message."); this._logger.error("this is an error message."); this._logger.warn("this is a warning message."); this._logger.info("this is an info message."); this._logger.config("this is a config message."); this._logger.debug("this is a debug message."); this._logger.trace("this is a trace message."); you can filter the output of the global logger or any specific logger instance by setting the level property.

Environment variables affecting crash reporting - Archive of obsolete content
moz_crashreporter_fulldump store full application memory in the minidump, so you can open it in a microsoft debugger.
...you can use this if you would rather use the jit debugger on windows with the symbol server, for example.
...you must use this to enable crash reporting on linux debug builds.

Space Manager Detailed Design - Archive of obsolete content
*/ prbool hasfloatdamage() { return !mfloatdamage.isempty(); } void includeindamage(nscoord aintervalbegin, nscoord aintervalend) { mfloatdamage.includeinterval(aintervalbegin + my, aintervalend + my); } prbool intersectsdamage(nscoord aintervalbegin, nscoord aintervalend) { return mfloatdamage.intersects(aintervalbegin + my, aintervalend + my); } #ifdef debug /** * dump the state of the spacemanager out to a file */ nsresult list(file* out); void sizeof(nsisizeofhandler* ahandler, pruint32* aresult) const; #endif private: // structure that maintains information about the region associated // with a particular frame struct frameinfo { nsiframe* const mframe; nsrect mrect; // rectangular region frameinfo* ...
... */ prbool hasfloatdamage() { return !mfloatdamage.isempty(); } void includeindamage(nscoord aintervalbegin, nscoord aintervalend) { mfloatdamage.includeinterval(aintervalbegin + my, aintervalend + my); } prbool intersectsdamage(nscoord aintervalbegin, nscoord aintervalend) { return mfloatdamage.intersects(aintervalbegin + my, aintervalend + my); } debug only methods /** * dump the state of the spacemanager out to a file */ nsresult list(file* out); void sizeof(nsisizeofhandler* ahandler, pruint32* aresult) const; unused / obsolete methods /* * get the frame that's associated with the space manager.
...from the current implementation, it might be worth verifying that the final result of the inserts is a correctly ordered list of bandrects (debug mode only).

Windows stub installer - Archive of obsolete content
the windows stub installer project resides at: <http://lxr.mozilla.org/seamonkey/sou...windows/setup/> how do we get setup to debug the windows stub installer?
... now you will find an installer *and* the xpcom.xpi and other debug xpis delivered to mozilla/dist/win32_d.obj/install.
... if you need to use vc++ to debug the installer: under project | settings | debug set "executable for debug session" to be the path to mozilla/dist/win32_d.obj/install/setup.exe set "working directory" to be the path to mozilla/dist/wind32_d.obj/install press f10 to step into the code how we get setup to debug the xpinstall engine from the windows stub installer?

Creating XULRunner Apps with the Mozilla Build System - Archive of obsolete content
mk_add_options moz_build_projects="xulrunner mccoy" mk_add_options moz_objdir=@topsrcdir@/../mccoybase # global options ac_add_options --enable-debug ac_add_options --disable-optimize # xulrunner options ac_add_app_options xulrunner --enable-application=xulrunner # mccoy options ac_add_app_options mccoy --enable-application=mccoy ac_add_app_options mccoy --with-libxul-sdk=../xulrunner/dist the first section tells mozilla what to build and where to put the resulting object files.
...in this case we're creating a debug build, so you'd have to change the relevant options if you want a release build instead.
...you can add other preferences for things like debugging, as mccoy does (e.g.

MacFAQ - Archive of obsolete content
lineservicemac.cpp", you'll see that it looks for "browser.chromeurl" before defaulting to navigator.xul, and this is called when an xulrunner app is already running, so: create a default preference of "browser.chromeurl" that points to your new "hiddenwindow" as such: "chrome://myxul/content/hiddenwindow.xul" next take the code below and drop it in, to create the hiddenwindow.xul (note: the debug function and nsicommandline try/catch can be removed, all you need is the window.arguments[0]) <?xml version="1.0"?> <window xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul" id="myxul_hidden" windowtype="myxul:hiddenwindow" title="" width="0" height="0" persist="screenx screeny width height sizemode" > <!-- load the mozilla helpers --> <script ty...
...pe="application/javascript" src="chrome://global/content/nsusersettings.js" /> <script><![cdata[ function debug(alogstring) { var mconsoleservice = components.classes["@mozilla.org/consoleservice;1"] .getservice(components.interfaces.nsiconsoleservice) mconsoleservice.logstringmessage("myxul: " + alogstring + "\n"); } function checkotherwindows() { var singletonwindowtype = nspreferences.copyunicharpref("toolkit.singletonwindowtype"); var windowmediator = components.classes["@mozilla.org/appshell/window-mediator;1"] .getservice(components.interfaces.nsiwindowmediator); var win = windowmediator.getmostrecentwindow(singletonwindowtype); if (win) { window.close(); win.f...
...ocus(); } } if (window.arguments && window.arguments[0]){ try { var cmdline = window.arguments[0] .queryinterface(components.interfaces.nsicommandline); for (var i = 0; i < cmdline.length; ++i) { debug(cmdline.getargument(i)) } } catch(ex) { debug(window.arguments[0]) // do something with window.arguments[0] //nspreferences.setunicharpref("myxul.cmdlinevalue", window.arguments[0]) } window.addeventlistener("load", checkotherwindows , false); } ]]></script> </window> ...

Extentsions FAQ - Archive of obsolete content
http://developer.mozilla.org/en/docs...pcom_component would anyone be able to suggest the best way to do source level debugging in a firefox extension?
... in the debug menu, uncheck exclude browser files.
... use the debugger by typing in a command like this: /break chrome://myextension/content/myfile.js 123 then i suggest using flat chrome.

Settings - Archive of obsolete content
the debugger has its own settings menu, which you can access from an icon in the toolbar: each setting is a simple on/off switch: auto prettify minified sources with this option enabled, the debugger will automatically detect minified js files and pretty-print them.
... show panes on startup when this option is enabled, the debugger's variables pane is visible when you first start the debugger.
... show original sources enabling this option will make the debugger use source maps, if they are available, to display the original source for code which has been combined, minified, or even compiled to javascript from a language like coffeescript.

Tools for game development - Game development
on this page you can find links to our game development tools articles, which eventually aims to cover frameworks, compilers, and debugging tools.
... toolchain for developing and debugging games how does this differ from normal web app debugging?
...a lot of this is going to be covered by will in tools, but here we should provide a kind of practical toolchain tutorial for debugging games, with links to will's stuff: basic tools overview shader editor performance tools (still in production, estimated early 2014) ...

CSS building blocks - Learn web development
this module looks at the cascade and inheritance, all the selector types we have available, units, sizing, styling backgrounds and borders, debugging, and lots more.
... debugging css sometimes when writing css you will encounter an issue where your css doesn't seem to be doing what you expect.
... this article will give you guidance on how to go about debugging a css problem, and show you how the devtools included in all modern browsers can help you find out what is going on.

Common questions - Learn web development
every browser features a set of devtools for debugging html, css, and other web code.
... what tools are available to debug and improve website performance?
... this set of articles shows you how to use the developer tools in firefox to debug and improve performance of your website, using the tools to check memory usage, the javascript call tree, the number of dom nodes being rendered, and more.

Solve common problems in your JavaScript code - Learn web development
debugging javascript what are the basic types of error?
... how do you use breakpoints and other javascript debugging features?
... for more information on javascript debugging, see handling common javascript problems.

Ember resources and troubleshooting - Learn web development
how do i debug what's going on in the framework?
... for framework-specific things, there is the ember-inspector add-on, which allows inspection of: routes & controllers components services promises data (i.e: from a remote api — from ember-data, by default) deprecation information render performance for general javascript debugging, check out our guides on javascript debugging as well as interacting with the browser's other debugging tools.
...both of these files are generated with sourcemaps, so when you open the vendor.js or {app-name}.js to search for relevant code, when a debugger is placed, the sourcemap will be loaded and the breakpoint will be placed in the pre-transpiled code for easier correlation to your project code.

Benchmarking
debug builds debug builds (--enable-debug) and non-optimized builds (--disable-optimize) are much slower.
...in particular, "gc poisoning" is used in all debug builds, and in optimized nightly builds (but not opt developer edition or beta builds).
... another option that is on by default in non-release builds is the preference javascript.options.asyncstack, which provides better debugging information to developers.

Creating a Login Manager storage module
to see some debugging output in the console set signon.debug to true using about:config.
...torage/sample;1", classid: components.id("{364a118c-747a-4f6d-ac63-2d2998e5a5c1}"), queryinterface: xpcomutils.generateqi([ci.nsiloginmanagerstorage]), // this registers the category for overriding the built-in nsiloginmanagerstorage _xpcom_categories: [ { category: "login-manager-storage", entry: "nsiloginmanagerstorage" } ], // console logging service, used for debugging.
... getservice(ci.nsiconsoleservice); return this.__logservice; }, log: function (message) { dump("sampleloginmanager: " + message + "\n"); this._logservice.logstringmessage("sampleloginmanager: " + message); }, // logs function name and arguments for debugging stub: function(arguments) { var args = []; for (let i = 0; i < arguments.length; i++) args.push(arguments[i]) this.log("called " + arguments.callee.name + "(" + args.join(",") + ")"); }, init: function slms_init() { this.stub(arguments); }, initwithfile: function slms_initwithfile(ainputfile, aoutputfile) { this.stub(arguments); }, addlogin: function s...

How to Report a Hung Firefox
submit a crash report for a hung firefox the easiest way to help the firefox stability team to debug these kinds of hangs is to make the hung firefox crash and submit a crash report.
... instead of crashing firefox, more advanced developers who know how to use a debugger can try attaching to the firefox process and debugging in place.
... this is only useful if you have firefox debug symbols, which are available on windows from the mozilla symbol server.

AsyncShutdown.jsm
// collect any information that may be useful for debugging shutdown issues with this blocker return status; } }); in this example, at some point during phase profilebeforechange, function condition will be called.
...in this case, a crash report is produced, with information on all the shutdown blockers that have not been resolved, and all the additional debug information returned by calls to info().
...used for debugging/error reporting.

Investigating leaks using DMD heap scan mode
prerequisites a debug dmd build of firefox.
...this is mostly useful for larger objects, and you can potentially combine this with debugging information to figure out exactly what field this is.
... example analysis of block_analyzer.py results in one debugging session where i was investigating the leak from bug 1451985, i eventually reduced the list of entries until this was the most suspicious looking entry: 0x7f0892f29630 size = 392 bytes at byte offset 56 mozilla::dom::scriptloader::processexternalscript[...] [...] i went to that line of scriptloader::processexternalscript(), and it contained a call to scriptloader::createloadrequest().

NSS_3.12.1_release_notes.html
both debug and optimized builds are provided.
... go to the subdirectory for your platform, dbg (debug) or opt (optimized), to get the tar.gz or zip file.
...414003: crash [[@ cert_decodecertpackage] sometimes with this testcase bug 415167: memory leak in certutil bug 417399: arena allocation results are not checked in pkix_pl_infoaccess_parselocation bug 420644: improve ssl tracing of key derivation bug 426886: use const char* in pk11_importcertforkey bug 428103: cert_encodesubjectkeyid is not defined in any public header file bug 429716: debug builds of libpkix unconditionally dump socket traffic to stdout bug 430368: vfychain -t option is undocumented bug 430369: vfychain -o succeeds even if -pp is not specified bug 430399: vfychain -pp crashes bug 430405: error log is not produced by cert_pkixverifycert bug 430743: update ssltap to understand the tls session ticket extension bug 430859: pkix: policy mapping fails verifica...

NSS_3.12.2_release_notes.html
both debug and optimized builds are provided.
... go to the subdirectory for your platform, dbg (debug) or opt (optimized), to get the tar.gz or zip file.
...de bug 451024: certutil.exe crashes with segmentation fault inside pr_cleanup bug 451927: security/coreconf/winnt6.0.mk has invalid defines bug 452751: slot leak in pk11_findslotsbynames bug 452865: remove obsolete linker flags needed when libnss3 was linked with libsoftokn3 bug 454961: fix the implementation and use of pr_fgets in signtool bug 455348: change hyphens to underscores in debug_$(shell whoami).

nss tech note1
sec_asn1_debug_break: makes the decoder assert when processing the template.
...it is useful to debug your templates or when writing new templates if they don't work.
... sec_quickderdecodeitem supports sec_asn1_optional together with sec_asn1_skip sec_asn1_debug_break is not supported by sec_asn1decodeitem </tt> ...

Small Footprint
on a recent build, the length of js.jar was 603,127 bytes corresponding to 1,171,708 bytes of all uncompressed rhino classes with debug information included.
... debug information debug information in rhino classes consumes about 25% of code size and if you can live without that, you can recompile rhino to remove it.
...to build such minimalist jar without debug information, run the following command from the top directory of rhino distribution: ant clean ant -ddebug=off -dno-regexp=true -dno-e4x=true smalljar if you omit -dno-regexp=true, then the resulting smalljs.jar will include regular expression support.

JSAPI User Guide
your program will be easier to debug.
...these two functions, both available only in debug builds, are especially useful for debugging gc-related crashes: use js_setgczeal to enable extra garbage collection.
...it's for development and debugging only, because the extra garbage collection makes js very slow.

JS_Add*Root
that could cause sporadic crashes during garbage collection, which can be hard to debug.) the variable must remain in memory until the balancing call to js_removeroot.
...typically name is a static string constant, identifying the source location of the call to js_addnamedroot for debugging purposes.
... js_dumpnamedroots can be used to access this information from a debugger.

Parser API
interface debuggerstatement <: statement { type: "debuggerstatement"; } a debugger statement.
... note: the debugger statement is new in ecmascript 5th edition, although spidermonkey has supported it for years.
... debuggerstatement([loc]) loc: sourcelocation returns: customstatement callback to produce a custom debugger statement node.

jsdIStackFrame
js/jsd/idl/jsdidebuggerservice.idlscriptable please add a summary to this article.
...see the version_* consts on jsdidebuggerservice.
... isdebugger boolean true if stack frame represents a frame created as a result of a debugger evaluation.

Frequently Asked Questions
comparing an nscomptr to a raw xpcom interface pointer declaring an nscomptr to a forward-declared class not linking to xpcom not including nscomptr.h different settings of nscap_feature_debug_ptr_types runtime errors ns_assertion "queryinterface needed" may be caused by a class that derives from a given interface, when you forgetting to also specify the interface name in the ns_impl_isupports / ns_impl_threadsafe_isupports macro.
...for debugging purposes you can write printf("%x\n", mynscomptr.get()); how do i...
... make an nscomptr leak (for a debug test)?

Index
29 gloda debugging the gloda code has log4moz logging statements spread throughout.
...the data will come from a custom header labeled x-superfluous 114 using mapi with thunderbird's windows 7 developer builds thunderbird debug, thunderbird mapi (messaging application programming interface) is a windows feature that allows applications to send files via a system's default mail application.
...if you want to set a debug build as the default mail client, you need configure it manually: 115 using the multiple accounts api by alec flett alecf@flett.org 118 libmime content type handlers by richard h.

Mailnews and Mail code review requirements
rubber-stamp approvals for intermittently failing ("orange") test fixes/debugging in order to make it easier to debug and fix tests that fail intermittently ("intermittent orange" tests), we have created the following two rubber-stamps based on this proposal on the tb-planning mailing list.
... the procedure to use these is to be sure to: include "rs=simple-orange-fix" or "rs=orange-debugging" in the first line of the commit message paste a link to the pushed commit with the rubber stamp in the bug make sure you pasted a link to any try-server pushes of the patch in the bug rs=simple-orange-fix requirements: the patch is fixing an intermittent orange test failure.
... rs=orange-debugging requirements: the patch is trying to fix an intermittent orange test failure.

Set a breakpoint - Firefox Developer Tools
there are many different types of breakpoint that can be set in the debugger; this article covers standard (unconditional) breakpoints and conditional breakpoints.
... breakpoints in brief breakpoints are very useful when debugging javascript — you basically set a point in your code where you would like execution of the code to pause.
... continue to here: when stepping through code, this option tells the debugging to continue execution through to this point.

Set a conditional breakpoint - Firefox Developer Tools
a normal breakpoint is just associated with a line: when the program reaches that line, the debugger pauses.
...when the program reaches the line, the debugger pauses only if the breakpoint's specified expression evaluates to true.
... this makes it possible to debug specific scenarios, such as bugs that only happen on odd entries in a list, or errors that occur the last time through a loop, for example.

Step through code - Firefox Developer Tools
when the debugger is stopped at a breakpoint, you can step through it using four buttons in the toolbar: in order, the buttons are: play: run to the next breakpoint step over: advance to the next line in the same function.
... step in: advance to the next line in the function, unless on a function call, in which case enter the function being called step out: run to the end of the current function, in which case, the debugger will skip the return value from a function, returning execution to the caller split console when paused, you can press the esc key to open and close the split console to gain more insight into errors and variables: pause on breakpoints overlay since firefox 70, when your code is paused on a breakpoint an overlay appears on the viewport of the tab you are debugging.
... if you want to turn this feature off, since firefox 71 you can do so by going to about:config in a new tab, setting the devtools.debugger.features.overlay pref to false, and restarting the browser.

Set a logpoint - Firefox Developer Tools
the logpoint is especially useful in cases where breaking the execution breaks testing procedures, such as when you are debugging popup windows, or executing focus-related logic.
... to create a logpoint: right click on a line number in the debugger panel and pick add log action from the context menu.
...you can make it easier to see the message by opening a split console under the debugger.

Set event listener breakpoints - Firefox Developer Tools
starting with firefox 69, debugging an application that includes event handlers is simplified because the debugger now includes the ability to automatically break when the code hits an event handler.
... using a standard event breakpoint to use an event breakpoint, you open up the javascript debugger, and find and expand the event listener breakpoints section in the right hand column.
... this is also useful when debugging code that you're unfamiliar with, to save time over hunting down your event handler within your code, or when trying to understand why a web site isn't working as expected in your browser.

All keyboard shortcuts - Firefox Developer Tools
owser console ctrl + shift + j cmd + shift + j ctrl + shift + j open browser toolbox ctrl + alt + shift + i cmd + opt + shift + i ctrl + alt + shift + i open scratchpad shift + f4 shift + f4 * shift + f4 open webide shift + f8 shift + f8 * shift + f8 storage inspector shift + f9 shift + f9 * shift + f9 open debugger 3 ctrl + shift + z cmd + opt + z ctrl + shift + z 1.
... enter return enter debugger command windows macos linux close current file ctrl + w cmd + w ctrl + w search for a string in the current file ctrl + f cmd + f ctrl + f search for a string in all files ctrl + shift + f cmd + shift + f ctrl + shift + f find next in the current file ctrl + g cmd + g ctrl + g search for script...
... note: before firefox 66, the combination ctrl + shift + s on windows and linux or cmd + opt + s on macos would open/close the debugger.

Tips - Firefox Developer Tools
web console in all panels: esc opens the split console; useful when debugging, or inspecting nodes in the command line: $0 references the currently selected node.
... debugger skip javascript libraries in debugging sessions via the black box icon ().
... check "disable http cache (when toolbox is open)" in the settings to disable the network cache while debugging network issues.

console - Web APIs
the console object provides access to the browser's debugging console (e.g.
... console.debug() outputs a message to the console with the log level debug.
...for example, given this code: console.log("this is the outer level"); console.group("first group"); console.log("in the first group"); console.group("second group"); console.log("in the second group"); console.warn("still in the second group"); console.groupend(); console.log("back to the first group"); console.groupend(); console.debug("back to the outer level"); the output looks like this: timers you can start a timer to calculate the duration of a specific operation.

Console API - Web APIs
the console api provides functionality to allow developers to perform debugging tasks, such as logging messages or the values of variables at set points in your code, or timing how long an operation takes to complete.
...find out about these at: google chrome devtools implementation safari devtools implementation usage is very simple — the console object — available via window.console, or workerglobalscope.console in workers; accessible using just console — contains many methods that you can call to perform rudimentary debugging tasks, generally focused around logging various values to the browser's web console.
... interfaces console provides rudimentary debugging functionality, including logging, stack traces, timers, and counters.

Pinch zoom gestures - Web APIs
<body onload="init();" style="touch-action:none"> <div id="target">touch and hold with 2 pointers, then pinch in or out.<br/> the background color will change to pink if the pinch is opening (zoom in) or changes to lightblue if the pinch is closing (zoom out).</div> <!-- ui for logging/debugging --> <button id="log" onclick="enablelog(event);">start/stop event logging</button> <button id="clearlog" onclick="clearlog(event);">clear the log</button> <p></p> <output></output> </body> miscellaneous functions these functions support the application but aren't directly involved in the event flow.
... function remove_event(ev) { // remove this event from the target's cache for (var i = 0; i < evcache.length; i++) { if (evcache[i].pointerid == ev.pointerid) { evcache.splice(i, 1); break; } } } event logging these functions are used to send event activity to the application's window (to support debugging and learning about the event flow).
... // log events flag var logevents = false; // logging/debugging functions function enablelog(ev) { logevents = logevents ?

A re-introduction to JavaScript (JS tutorial) - JavaScript
this is very rarely what you want — in fact it's worth specifically labeling deliberate fallthrough with a comment if you really meant it to aid debugging: switch (a) { case 1: // fallthrough case 2: eatit(); break; default: donothing(); } the default clause is optional.
...the name also shows up in the debugger and some stack traces, which can save you time when debugging.
...this is useful for debugging our person objects: var s = new person('simon', 'willison'); s.tostring(); // [object object] person.prototype.tostring = function() { return '<person: ' + this.fullname() + '>'; } s.tostring(); // "<person: simon willison>" remember how avg.apply() had a null first argument?

Object.create() - JavaScript
this is especially true when debugging, since common object-property converting/detecting utility functions may generate errors, or simply lose information (especially if using silent error-traps that ignore errors).
...() // throws error: ocn.tostring is not a function > oco.valueof() // shows {} > ocn.valueof() // throws error: ocn.valueof is not a function > oco.hasownproperty("p") // shows "true" > ocn.hasownproperty("p") // throws error: ocn.hasownproperty is not a function > oco.constructor // shows "object() { [native code] }" > ocn.constructor // shows "undefined" as said, these differences can make debugging even simple-seeming problems quickly go astray.
... for example: a simple common debugging function: // display top-level property name:value pairs of given object function showproperties(obj){ for(var prop in obj){ console.log(prop + ": " + obj[prop] + "\n" ); } } not such simple results: (especially if silent error-trapping had hidden the error messages) ob={}; ob.po=oco; ob.pn=ocn; // create a compound object using the test objects from above as property values > showproperties( ob ) // display top-level properties - po: [object object] - error: cannot convert object to primitive value note that only first property gets shown.

Lexical grammar - JavaScript
they can also be used to disable code to prevent it from being executed; this can be a valuable debugging tool.
... keywords reserved keywords as of ecmascript 2015 break case catch class const continue debugger default delete do else export extends finally for function if import in instanceof new return super switch this throw try typeof var void while with yield future reserved keywords the following are reserved as future keywords by the ecmascript specification.
... `string text line 1 string text line 2` `string text ${expression} string text` tag `string text ${expression} string text` automatic semicolon insertion some javascript statements must be terminated with semicolons and are therefore affected by automatic semicolon insertion (asi): empty statement let, const, variable statement import, export, module declaration expression statement debugger continue, break, throw return the ecmascript specification mentions three rules of semicolon insertion.

Content Scripts - Archive of obsolete content
this makes your code easier to maintain, secure, debug and review.
...this makes your code easier to maintain, secure, debug and review.

page-mod - Archive of obsolete content
this makes your code easier to maintain, secure, debug and review.
...this makes your code easier to maintain, secure, debug and review.

simple-storage - Archive of obsolete content
important: if you use this method, you must end your debugging session by quitting firefox normally, not by cancelling the shell command.
... accessing storage from the console in the add-on debugger, you can access your add-on's simple-storage programmatically from the console using the following: loader.modules['resource://gre/modules/commonjs/sdk/simple-storage.js'].exports.storage clarification from mozilla needed: writing the above line in add-on debugger console results in "referenceerror: loader is not defined".

Release notes - Archive of obsolete content
add-on debugger now includes a console and a scratchpad.
... firefox 31 highlights add-on debugger added the ability to convert between high-level browserwindow objects and dom windows, and between high-level tab objects and xul tabs.

Tutorials - Archive of obsolete content
creating reusable modules structure your add-on in separate modules to make it easier to develop, debug, and maintain.
... add-on debugger debug your add-on's javascript.

Dehydra Function Reference - Archive of obsolete content
it is a mainly useful for debugging dehydra for rooting bugs.
... gczeal is only enabled when spidermonkey and dehydra are compiled with debug macro defined.

Running Tamarin performance tests - Archive of obsolete content
adb 'adb' stands for android debug bridge.
...under settings->applications->development, is usb debugging enabled?

Deprecated and defunct markup - Archive of obsolete content
--neil 03 march 2011 <sidebarheader> not true, still in use --neil 03 march 2011 <slider> (clickable tray in <scrollbar> which holds <thumb>; do not use alone) also used as part of <scale> --neil 03 march 2011 <spinner> (spinbox; <spinbuttons> with a textbox whereby spinning affects value in textbox; not usable) <spring> (use @flex instead) <strut> (replaced by @debug?) <tabcontrol> (contained tabbox and tabpanel) <text> (like <label> or <description> but does not wrap; like <label crop="end">; had been used in menus/toolbars) <textfield> (like <textbox>) <thumb> (<button> with deprecated <gripper>; implements sliding box in center of scrolbar) <title> (to add a caption on a <titledbox> <titledbox> (box with a frame) <titledbutton> (attemp...
...use only; part of xbl for <tree>) <treefoot> (old/experimental and unsupported xul tags) <treeindentation> (old/experimental and unsupported xul tags) was a part of the old <tree> that predated <outliner> that was not converted to <listbox>--neil 03 march 2011 <treeicon> (old/experimental and unsupported xul tags) <treerows> (internal use only; part of xbl for <tree>) attributes @debug="true" provided struts and springs around boxes to facilitate identification of flex issues but does not seem to work now you need a special debug_layout build --neil 03 march 2011 references xul element reference by neal deakin rapid application development with mozilla, by nigel mcfarlane ...

Index - Archive of obsolete content
both types of builders implement the nsixultemplatebuilder interface, while the tree builder also implements the nsixultreebuilder interface.</tree> 946 template logging debugging problems with a template can be difficult as many problems are logic errors that are often not possible to determine automatically.
...fortunately, some debugging and logging support is provided with templates that may help.

Introduction to XUL - Archive of obsolete content
the menu bar has a menu, file, with a single menu item that dumps "hello world!" to the debug console when selected.
...this handler fires when the menu is selected by the user, and it dumps the text "hello world!" to the debug console.

XUL Structure - Archive of obsolete content
to disable this mechanism, it is necessary to change the preference nglayout.debug.disable_xul_cache.
...or, just manually edit your user.js preferences file and add the following line: pref("nglayout.debug.disable_xul_cache", true); there are usually three different parts to a chrome package, although they are all optional.

Building XULRunner with Python - Archive of obsolete content
it effectively specifies a release build that is not particularly suitable for debugging xulrunner itself.
... using python in xul applications add the following to yourprefs.js during development pref("browser.dom.window.dump.enabled", true); pref("javascript.options.showinconsole", true); pref("javascript.options.strict", true); pref("nglayout.debug.disable_xul_cache", true); pref("nglayout.debug.disable_xul_fastload", true); html <script> tags specify that python is used withtype="application/x-python" attribute.

2006-12-01 - Archive of obsolete content
debugging firefox extesnion?
... a tip on how to debug firefox extensions using a debugger.

NSPR Release Engineering Guide - Archive of obsolete content
feature complete update ...pr/include/prinit.h with release numbers build all targets, debug and optimized on all platforms using local directories run the test suite on all targets verify release numbers show up in binaries resolve testing anomalies tag the tree with nsprpub_release_x_y_z_beta beta release checkout a whole new tree using the tag from above build all targets, debug and optimized on all platforms using the command: gmake release mdist=<dir>/mdist build_number=vx.y.z [build_opt=1 | use_debug_rtl=1] copy the bits from mdist to /share/builds/components/nspr20/.vx.y.z 1 run ex...
...plode.pl run the test suite on all targets, using binaries & headers from shipped bits resolve testing anomalies tag the tree with nsprpub_release_x_y[_z] release candidate checkout a whole new tree using tag (including fixes) tag the treey with nsprpub_release_x_y_z build all targets, debug and optimized on all platforms using the command: gmake release mdist=<dir>/mdist build_number=vx.y.z [build_opt=1 | use_debug_rtl=1] copy the bits from mdist to /share/builds/components/nspr20/.vx.y.z in /share/builds/components/nspr20/ run the following scripts: explode.pl rename.sh symlink.sh rtm bits rename the .vx.y.z directory to vx.y.z (remove the hidden directory 'dot').

Object.prototype.unwatch() - Archive of obsolete content
description the javascript debugger has functionality similar to that provided by this method, as well as other debugging options.
... for information on the debugger, see venkman.

Object.prototype.watch() - Archive of obsolete content
the javascript debugger has functionality similar to that provided by this method, as well as other debugging options.
... for information on the debugger, see venkman.

Building Mozilla XForms - Archive of obsolete content
2 on a dual core processor) ac_add_options --enable-extensions="default,xforms" ac_add_options --disable-debug ac_add_options --enable-optimize ac_add_options --disable-tests for a debug build, you could use this configuration: .
... $topsrcdir/browser/config/mozconfig mk_add_options moz_co_project=browser mk_add_options moz_objdir=@topsrcdir@/obj-@config_guess@ ac_add_options --enable-extensions="default,xforms" ac_add_options --enable-debug ac_add_options --disable-optimize ac_add_options --disable-tests building now that you have everything ready, you can rebuild mozilla with the same command you used before to build firefox without xforms.

Developer Tools - MDN Web Docs Glossary: Definitions of Web-related terms
developer tools (or "development tools" or short "devtools") are programs that allow a developer to create, test and debug software.
...they let users inspect and debug the page's html, css, and javascript, allow to inspect the network traffic it causes, make it possible to measure it's performance, and much more.

Index - MDN Web Docs Glossary: Definitions of Web-related terms
111 developer tools codingscripting, developer tools, glossary developer tools (or "development tools" or short "devtools") are programs that allow a developer to create, test and debug software.
...an ide normally consists of a source code editor, build automation tools and a debugger.

Cascade and inheritance - Learn web development
!important changes the way the cascade normally works, so it can make debugging css problems really hard to work out, especially in a large stylesheet.
... overview: building blocks next in this module cascade and inheritance css selectors type, class, and id selectors attribute selectors pseudo-classes and pseudo-elements combinators the box model backgrounds and borders handling different text directions overflowing content values and units sizing items in css images, media, and form elements styling tables debugging css organizing your css ...

Styling tables - Learn web development
the next article explores debugging css — how to solve problems such as layouts not looking like they should, or properties not applying when you think they should.
...us overview: building blocks next in this module cascade and inheritance css selectors type, class, and id selectors attribute selectors pseudo-classes and pseudo-elements combinators the box model backgrounds and borders handling different text directions overflowing content values and units sizing items in css images, media, and form elements styling tables debugging css organizing your css ...

How CSS works - Learn web development
understanding the dom helps you design, debug and maintain your css because the dom is where your css and the document's content meet up.
... the updated output is as follows: in our debugging css article in the next module we will be using browser devtools to debug css problems, and will learn more about how the browser interprets css.

What went wrong? Troubleshooting JavaScript - Learn web development
the name of the javascript file, which links through to the debugger tab of the developer tools.
...add the following code on line 49: console.log(loworhi); note: console.log() is a really useful debugging function that prints a value to the console.

Handling common HTML and CSS problems - Learn web development
in our debugging html and debugging css articles, we provided some really basic guidance on debugging html/css — if you are not familiar with the basics, you should definitely study these articles before carrying on.
...see debug your css with outline visualizations for more details.

Introduction to cross browser testing - Learn web development
before you even get to cross browser issues, you should have already fixed out bugs in your code (see debugging html, debugging css, and what went wrong?
...finding out the cause of the bug involves the same strategy as any web development bug (again, see debugging html, debugging css, and what went wrong?

Simple SeaMonkey build
make -f client.mk for a debug build, you need different configuration options in your .mozconfig file.
... mk_add_options moz_objdir=/path/to/comm-central/obj-sm-debug ac_add_options --enable-application=suite ac_add_options --enable-debug ac_add_options --disable-optimize normally a shared build suffices for debugging purposes but current nightly releases are actually static builds which require even more memory to link.

Simple Sunbird build
# build make -f client.mk for a debug build, you need different configuration options in your .mozconfig file.
...mk_add_options moz_objdir=@topsrcdir@/objdir-sb-debug ac_add_options --enable-application=calendar ac_add_options --enable-debug ac_add_options --disable-optimize running sunbird the sunbird executable can be found in objdir-sb-release/mozilla/dist/bin/ (on mac, objdir-sb-release/dist/calendar.app/contents/macos/).

mach
if it works, you can look at compiler warnings: $ ./mach warnings-list try running the program: $ ./mach run try running your program in a debugger: $ ./mach run --debug try running some tests: $ ./mach xpcshell-test services/common/tests/unit/ or run an individual test: $ ./mach mochitest browser/base/content/test/general/browser_pinnedtabs.js you run mach from the source directory, so you should be able to use your shell's tab completion to tab-complete paths to tests.
...here is a minimal mach command module: from __future__ import print_function, unicode_literals from mach.decorators import ( commandargument, commandprovider, command, ) @commandprovider class machcommands(object): @command('doit', description='run it!') @commandargument('--debug', '-d', action='store_true', help='do it in debug mode.') def doit(self, debug=false): print('i did it!') from mach.decorators we import some python decorators which are used to define what python code corresponds to mach commands.

Performance best practices for Firefox front-end engineers
you can activate paint flashing for browser chrome by setting nglayout.debug.paint_flashing_chrome to true.
... you can activate paint flashing for web content by setting nglayout.debug.paint_flashing to true.

Geckoview-Junit Tests
@test fun contentcrashignored() { // cannot test x86 debug builds due to gecko's "ah_crap_handler" // that waits for debugger to attach during a sigsegv.
... assumethat(sessionrule.env.isdebugbuild && sessionrule.env.cpuarch == "x86", equalto(false)) running tests on try to run these tests on try, use something like: mach try fuzzy -q geckoview-junit --artifact or mach try -b do -p android-x86_64 -u geckoview-junit --artifact currently, geckoview-junit is only run on android-x86_64.

How to get a stacktrace for a bug report
mozilla's crash report server currently only has debug information for mozilla builds and thus the crash reporter cannot work if you use a build from a linux distribution or if you compile from source code.
... ubuntu: instructions from the ubuntu team opensuse: general instructions from opensuse fedora: capturing stack traces gentoo: debugging using gdb ...

Promise
promise catch( function onreject ); the following calls are therefore identical: p.then(undefined, logerror); p.catch(logerror); debugging by design, the instant state and value of a promise cannot be inspected synchronously from code, without calling the then() method.
... to help with debugging, only when inspecting a promise object manually, you can see more information as special properties that are inaccessible from code (this, at present, is implemented by randomizing the property name, for the lack of more sophisticated language or debugger support).

Mozilla projects on GitHub
debugger.html the debugger.html, a modern universal js debugger for firefox devtools, node, and every other js environment.
... fxdt-adapters the firefox developer tools adapter that lets you debug various remote targets from the firefox developer tools.

BloatView
how to build with bloatview build with --enable-debug or --enable-logrefcnt.
... bloatview and continuous integration bloatview runs on debug builds for many of the test suites mozilla has running under continuous integration.

DMD
add --debug to run under gdb.
...add --debug to run under lldb.

GC and CC logs
these logs can either be manually or automatically generated, and they can be generated in both debug and non-debug builds.
... from the commandline tldr: if you just want shutdown gc/cc logs to debug leaks that happen in our automated tests, you probably want something along the lines of: moz_disable_content_sandbox=t moz_cc_log_directory=/full/path/to/log/directory/ moz_cc_log_shutdown=1 moz_cc_all_traces=shutdown ./mach ...

Refcount tracing and balancing
how to build for refcount tracing build with --enable-debug or --enable-logrefcnt.
... however, having an nscomptr log and using it in the creation of the balance tree allows addref and release calls that we know are matched to be eliminated from the tree, so it makes it much easier to debug reference count leaks of objects that have a large amount of reference counting traffic.

javascript.options.showInConsole
type:boolean default value: false (true in debug builds) exists by default: yes application support:firefox 1.0 status: active introduction:2002-02-26 bugs: bug 125181 bug 337875 values false only errors and warnings from content code are shown.
... note: since the web console was introduced in firefox 4 specifically for debugging content, the default value for this preference has changed to true as of gecko 2.0.

Emscripten techniques
debugging out-of-memory problems a common bug to diagnose with emscripten is where a big game fails due to an out of memory error (oom) somewhere during load time.
...this article explains how to debug such problems.

Leak And Bloat Tests
manually running tests setting up build set up build thunderbird or seamonkey with your standard mozconfig file, but with the following options set: ac_add_options --enable-debug ac_add_options --enable-trace-malloc running the tests in your <objdir> run the following command: make mailbloat this will run the tests and produce some result files.
... see debugging memory leaks for more information on what to do with this data.

NSPR LOG FILE
for ms windows systems, you can set nspr_log_file to the special (case-sensitive) value windebug.
... this value causes logging output to be written using the windows function outputdebugstring(), which writes to the debugger window.

Building NSS
build_opt 0 build a debug (non-optimized) version of nss.
... 1 build an optimized (non-debug) version of nss.

JSS FAQ
how can i debug my ssl connection?
... check http://lxr.mozilla.org/mozilla/source/security/jss/org/mozilla/jss/ssl/sslsocket.java#730 how can i debug my ssl connection?

NSS_3.11.10_release_notes.html
both debug and optimized builds are provided.
... go to the subdirectory for your platform, dbg (debug) or opt (optimized), to get the tar.gz or zip file.

NSS 3.35 release notes
note that debug builds will use a lower count, for better performance in test environments.
... as a reminder, debug builds should not be used for production purposes.

NSS 3.52 release notes
bug 1630458 - fix problem of gyp msvc builds not producing debug symbol files.
... bug 1629105 - add pkcs11 v3.0 functions to module debug logger.

Python binding for NSS
add print_traceback(), print_cert() debugging support.
...debian) now takes optional command line arguments, -d or --debug will turn on debug options during the build.

NSS Tools
nss security tools newsgroup: mozilla.dev.tech.crypto overview the nss security tools allow developers to test, debug, and manage applications that use nss.
...this tool is very useful for debugging.

Rhino JavaScript compiler
-debug -g specifies that debug information should be generated.
...if optlevel is greater than zero, -debug may not be specified.

Self-hosted builtins in SpiderMonkey
debugging self-hosted code self-hosted code by default is hidden from client javascript code; in particular, self-hosted frames will be filtered out of the stack traces of exceptions.
... to include self-hosted frames in stack traces (in debug builds only), set the environment variable moz_show_all_js_frames.

JIT Optimization Outcomes
cantinlinedebuggee unable to inline function call.
... the interpreted callee function is being debugged by the debugger api.

JS::Add*Root
that could cause sporadic crashes during garbage collection, which can be hard to debug.) the variable must remain in memory until the balancing call to js::remove*root.
...typically name is a static string constant, identifying the source location of the call to js::addnamed*root for debugging purposes.

JS::Value
it is highly recommended that you develop and test with an --enable-debug build to detect most js::value misuse.
... debug builds will assert correct jsapi use in many other instances as well.

JSAPI reference
jsapi 26 js_call_tracer added in spidermonkey 1.8 obsolete since jsapi 23 js_call_value_tracer added in spidermonkey 1.8 obsolete since jsapi 23 js_call_object_tracer added in spidermonkey 1.8 obsolete since jsapi 23 js_call_string_tracer added in spidermonkey 1.8 obsolete since jsapi 23 js_call_double_tracer added in spidermonkey 1.8 obsolete since javascript 1.8.5 js_printtracethinginfo (debug-only) added in spidermonkey 1.8 obsolete since jsapi 16 miscellaneous gc apis: js_updatemalloccounter added in spidermonkey 17 js::setlargeallocationfailurecallback added in spidermonkey 31 js::setoutofmemorycallback added in spidermonkey 31 js_enumeratediagnosticmemoryregions added in spidermonkey 17 jsval_lock obsolete since jsapi 18 jsval_unlock obsolete since jsapi 18 js_lockgct...
...nce javascript 1.8.5 jsfun_getter obsolete since javascript 1.8.5 jsfun_setter obsolete since javascript 1.8.5 jsfun_global_parent obsolete since javascript 1.8.5 jsfun_heavyweight obsolete since jsapi 19 jsfun_lambda obsolete since jsapi 19 c++ features class jsautorequest class jsautolocalrootscope obsolete since javascript 1.8.5 class js::perfmeasurement (in jsperf.h) tracing and debugging js_setfunctioncallback added in spidermonkey 1.8.5 obsolete since jsapi 37 js_getfunctioncallback added in spidermonkey 1.8.5 obsolete since jsapi 37 ...

JSDBGAPI
typedef jsstackframe js_frameiterator js_getframescript js_getframepc js_getscriptedcaller js_stackframeprincipals js_evalframeprincipals js_getframeannotation js_setframeannotation js_getframeprincipalarray js_isnativeframe js_getframeobject js_getframescopechain js_getframecallobject js_getframethis js_getframefunction js_getframefunctionobject js_isconstructorframe js_isdebuggerframe js_getframereturnvalue js_setframereturnvalue js_getframecalleeobject js_getscriptfilename js_getscriptbaselinenumber js_getscriptlineextent js_getscriptversion js_gettopscriptfilenameflags js_getscriptfilenameflags js_flagscriptfilenameprefix jsfilename_null jsfilename_system jsfilename_protected evaluating debug code js_evaluateinstackframe examining object ...
...properties typedef jspropertydesc jspd_enumerate jspd_readonly jspd_permanent jspd_alias jspd_argument jspd_variable jspd_exception jspd_error typedef jspropertydescarray js_propertyiterator js_getpropertydesc js_getpropertydescarray js_putpropertydescarray hooks js_setdebuggerhandler js_setsourcehandler js_setexecutehook js_setcallhook js_setobjecthook js_setthrowhook js_setdebugerrorhook js_setnewscripthook js_setdestroyscripthook js_getglobaldebughooks js_setcontextdebughooks memory usage js_getobjecttotalsize js_getfunctiontotalsize js_getscripttotalsize system objects js_issystemobject js_newsystemobject profiling these functions can be used to profile a spidermonkey application using the mac profiler, shark.

Profiling SpiderMonkey
instructions 1.) get yourself an optimized libxul build of firefox, with debugger info.
...here's a sample mozconfig: mk_add_options moz_objdir=@topsrcdir@/ff-opt-libxul mk_add_options moz_make_flags=-j3 ac_add_options --enable-optimize ac_add_options --enable-libxul ac_add_options --enable-shark ac_add_options --enable-debugger-info-modules ac_add_options --enable-application=browser 2.) you'll want to run shark on both the browser and [xpcshell], since the host environments differ.

SpiderMonkey 1.8
two new functions, js_setgczeal and js_dumpheap, aim to help developers debug gc-related problems.
... these functions are only present in debug builds.

Setting up CDT to work on SpiderMonkey
step 1 - preparing a spidermonkey build for cdt to index all code, spidermonkey has to be built with debug information.
... the initial build was in clang, so the modified build commands look like this: mkdir _dbg.obj cd _dbg.obj cc='clang -qunused-arguments -fcolor-diagnostics' cxx='clang++ -qunused-arguments -fcolor-diagnostics' \ ../configure --enable-debug --disable-optimize --enable-debug-symbols note: if you want to use ccache, you can enable it by adding --with-ccache to the arguments list.

Mozilla Projects
the low level, yet flexible architecture (described here) provides an extremely powerful platform for implementing debugging and analysis features.
... we would like to use web replay to radically improve not just the debugging experience but the entire web development experience.

Exploitable crashes
a crash report from your debugger, your os, or mozilla crash-stats can tell you a lot about whether or not a crash is potentially exploitable.
...microsoft released a debugger extension tool in 2009 called "!exploitable".

Component Internals
component discovery does not currently happen automatically in non-debug builds of gecko, however.
... the smart pointer class, nscomptr, for example, which makes reference counting less tedious and error-prone, is not actually frozen, and neither is nsdebug, a class for aiding in tracking down bugs, nor is nsmemory, a class to ensure that everyone uses the same heap, generic factory, and module.

Setting up the Gecko SDK
most of the changes you make in the following steps apply to all configurations of the project (both debug and optimized), so select "all configurations" from the settings for dropdown menu: on the c/c++ tab, select the preprocessor category.
... plds4.lib plc4.lib embedstring.lib xpcomglue.lib both of these settings are shown below: the last change you need to make to set up the gecko sdk in your project is to change the "use run-time library" setting to "multithreaded dll." since this change is configuration dependent, you must make set the release configuration run-time library to the release multithreaded dll runtime and the debug configuration to the debug multithreaded dll runtime (this needs clarification): after making these changes, press ok.

Mozilla internal string guide
(in the future, these conversions may start asserting in debug builds that their input is in the permissible range.) if the input is actually in the latin1 range, each 16-bit code unit in narrowed to an 8-bit byte by removing the high half.
...g& url, prbool addprefix) { if (addprefix) { // must create a temporary buffer - string is multi-fragmented constexpr auto httpprefix = u"http://"_ns; addpage(promiseflatstring(httpprefix + modifiedurl)); } else { // might create a temporary buffer, does a runtime check addpage(promiseflatstring(url).get()); } } printf and a utf-16 string for debugging, it's useful to printf a utf-16 string (nsstring, nsautostring, etc).

Components.utils.reportError
this means you can use components.utils.reporterror to report debugging messages to the error console, just like dump() can be used to print messages to the native console.
... examples usage in an exception handler: try { this.could.raise.an.exception; } catch(e) { components.utils.reporterror(e); // report the error and continue execution } sending debugging messages to the error console: components.utils.reporterror("init() called"); ...

nsIDOMWindowUtils
will throw a dom security error if called without universalxpconnect privileges in non-debug builds.
... available to all callers in debug builds.

XPCOM Interface Reference
component; nsiprefbranchextensionmanager (toolkit)iaccessible2iaccessibleactioniaccessibleapplicationiaccessiblecomponentiaccessibleeditabletextiaccessiblehyperlinkiaccessiblehypertextiaccessibleimageiaccessiblerelationiaccessibletableiaccessibletable2iaccessibletablecelliaccessibletextiaccessiblevalueidispatchijsdebuggeramiinstallcallbackamiinstalltriggeramiwebinstallinfoamiwebinstalllisteneramiwebinstallpromptamiwebinstallerimgicacheimgicontainerimgicontainerobserverimgidecoderimgidecoderobserverimgiencoderimgiloaderimgirequestinidomutilsjsdistackframemoziasyncfaviconsmoziasynchistorymozicoloranalyzermozijssubscriptloadermozipersonaldictionarymoziplaceinfomoziplacesautocompletemoziregistrymozirepresentativeco...
...obsoletensidomstorageitemnsidomstoragelistnsidomstoragemanagernsidomstoragewindownsidomuserdatahandlernsidomwindownsidomwindow2nsidomwindowinternalnsidomwindowutilsnsidomxpathevaluatornsidomxpathexceptionnsidomxpathexpressionnsidomxpathresultnsidomxulcontrolelementnsidomxulelementnsidomxullabeledcontrolelementnsidomxulselectcontrolelementnsidomxulselectcontrolitemelementnsidatasignatureverifiernsidebugnsidebug2nsidevicemotionnsidevicemotiondatansidevicemotionlistenernsidialogcreatornsidialogparamblocknsidictionarynsidirindexnsidirindexlistenernsidirindexparsernsidirectoryenumeratornsidirectoryiteratornsidirectoryservicensidirectoryserviceprovidernsidirectoryserviceprovider2nsidiskcachestreaminternalnsidispatchsupportnsidocshellnsidocumentloadernsidownloadnsidownloadhistorynsidownloadmanagernsid...

NS_ASSERTION
in a debug build the failure text is written to console (stderr), into the nspr debug log, and on windows a dialog box is opened.
... the behavior of an assertion failure can be controlled using the xpcom_debug_break environment variable.

Troubleshooting XPCOM components registration
registration failure if the module is loading correctly but doesn't register its components, try adding calls to components.utils.reporterror("debug me!"); in nsgetmodule() and other functions to try and find any errors.
...(the -r switch from gnu ldd lists function relocations; adjust as suitable for your version) trace shared library loading by setting the environment variable ld_debug=all while launching firefox (see `man ld.so` for details).

MailNews fakeserver
e transaction the transaction is an object with two properties: us, and them; us is an array of responses we sent, them an array of commands received resettest none nothing prepares the server for the next test without closing the connection start port number nothing starts the server listening stop none nothing stops the server and closes the connection using fakeserver in qa testing debug output from fakeservers it is possible to get the fakeservers to dump to the console the commands they have sent and received.
... to enable/disable debugging, call setdebuglevel on your nsmailserver instance with one of the following options: const fsdebugnone = 0; // dump nothing const fsdebugrecv = 1; // dump just the received commands const fsdebugrecvsend = 2; // dump received + sent commands, no data const fsdebugall = 3; // dump everything debugging is set to "none" by default.

Using the Mozilla source server
the nightly debug builds are now also source indexed so that by following a couple of simple steps you can also have the source code served to you for debugging without a local build what you'll need windbg or visual studio (note: express editions will not work, but windbg is a free download) a nightly build that was created after april 15, 2008; go to the /pub/firefox/nightly/latest-mozilla-central/ folder and grab the installer for builds predating the switch to mercurial, you'll need cvs.exe, added to your path (the cvs.exe from mozillabuild has problems, use this one instead) note: do not use the cvs from mozillabuild, it will not work!
... start debugging your program.

Int64
tosource() this method is for internal debugging use only.
... warning: do not rely on the value returned by this method, as it's subject to change at any time, depending on the debugging needs of the developers.

UInt64
tosource() this method is for internal debugging use only.
... warning: do not rely on the value returned by this method, as it's subject to change at any time, depending on the debugging needs of the developers.

Application - Firefox Developer Tools
the application panel provides tools for inspecting and debugging modern web apps (also known as progressive web apps).
... finding an example if you want to test this functionality and you don't have a handy pwa available, you can grab one of our simple examples to use: add to homescreen demo: shows pictures of foxes (source code | live version) js13kpwa demo: show information on entries to the js13k annual competition (source code | live version) how to debug service workers inspect web app manifests ...

Browser Console - Firefox Developer Tools
to enable it set the devtools.chrome.enabled preference to true in about:config, or set the "enable browser chrome and add-on debugging toolboxes" (firefox 40 and later) option in the developer tool settings.
...to enable it set the devtools.chrome.enabled preference to true in about:config, or set the "enable chrome debugging" option in the developer tool settings.

Break on DOM mutation - Firefox Developer Tools
once you set the breakpoint, go to the debugger.
... when you execute the code, the debugger will pause execution when the dom mutation occurs.

How to - Firefox Developer Tools
these articles describe how to use the debugger.
... access debugging in add-onsbreaking on exceptionsdebug eval sourcesdisable breakpointsexamine, modify, and watch variableshighlight and inspect dom nodesignore a sourceopen the debuggerpretty-print a minified filesearchset a breakpointset a conditional breakpointset watch expressionsstep through codeuse a source mapuse watchpoints ...

Source map errors - Firefox Developer Tools
you may encounter this when trying to open one of the original sources in the debugger.
... the message looks a little different in this case: in this case, the error will also be displayed in the source tab in the debugger: networkerror when attempting to fetch resource a bug in firefox prevents it from loading source maps for web extensions.

Dominators view - Firefox Developer Tools
clicking the file name will take you to that spot in the debugger.
... using the call stack view finally, you can switch to the call stack view, see where the objects are being allocated, and jump to that point in the debugger: ...

Toolbox - Firefox Developer Tools
there are a few different ways to open the toolbox: select "toggle tools" from the web developer menu (under "tools" on os x and linux, or "firefox" on windows) click the wrench icon (), which is in the main toolbar or under the hamburger menu (), then select "toggle tools" activate any tool hosted in the toolbox (for example, the javascript debugger or the page inspector) press ctrl + shift + i on windows and linux, or cmd + opt + i on os x.
...the array may include the following tools: web console javascript debugger page inspector style editor profiler network monitor note that not all the hosted tools are always listed here: only the tools actually available in this context are shown (for example, not all tools support remote debugging yet, so if the debugging target is not the firefox instance that launched the window, not all the hosted tools will be shown).

Console messages - Firefox Developer Tools
click the link to open the file in the debugger.
...this enables you to use the web console to debug server-side code.

Rich output - Firefox Developer Tools
the output will look something like this: console.log(todolist) array(4) [ {…}, {…}, {…}, {…} ] debugger eval code:1:9 undefined if you expand objects, such as arrays, you get slightly different content.
..."done", description: "morning pages", datecreated: 1552404478137 } ​ 1: object { status: "in progress", description: "refactor styles", datecreated: 1552404493169 } ​ 2: object { status: "to do", description: "create feedback form", datecreated: 1552404512630 } ​ 3: object { status: "to do", description: "normalize table", datecreated: 1552404533790 } ​ length: 4 ​ <prototype>: array [] debugger eval code:1:9 undefined highlighting and inspecting dom nodes if you hover the mouse over any dom element in the console output, it's highlighted on the page: in the screenshot above you'll also see a blue "target" icon next to the node in the console output: click it to switch to the inspector with that node selected.

Multi-touch interaction - Web APIs
<body onload="init();" style="touch-action:none"> <div id="target1"> tap, hold or swipe me 1</div> <div id="target2"> tap, hold or swipe me 2</div> <div id="target3"> tap, hold or swipe me 3</div> <!-- ui for logging/debugging --> <button id="log" onclick="enablelog(event);">start/stop event logging</button> <button id="clearlog" onclick="clearlog(event);">clear the log</button> <p></p> <output></output> </body> miscellaneous functions these functions support the application but aren't directly involved with the event flow.
... 1: // single touch point ev.target.style.background = "yellow"; break; case 2: // two simultaneous touch points ev.target.style.background = "pink"; break; default: // three or more simultaneous touches ev.target.style.background = "lightblue"; } } event logging these functions are used send to event activity to the application window (to support debugging and learning about the event flow).

PromiseRejectionEvent - Web APIs
these events are particularly useful for telemetry and debugging purposes.
... examples this simple example catches unhandled promise rejections and logs them for debugging purposes.

RTCIceCandidate.relatedPort - Web APIs
they may in fact be omitted for security reasons, but if present can be a useful tool during debugging.
... example in this example, the candidate's type is checked, and then debugging output is presented, based on the candidate type, including the candidate's type, address (ip and port), and related address (relatedaddress and relatedport).

Using Service Workers - Web APIs
=> { return promise.all(keylist.map((key) => { if (cachekeeplist.indexof(key) === -1) { return caches.delete(key); } })); }) ); }); developer tools chrome has chrome://inspect/#service-workers, which shows current service worker activity and storage on a device, and chrome://serviceworker-internals, which shows more detail and allows you to start/stop/debug the worker process.
... firefox has also started to implement some useful tools related to service workers: you can navigate to about:debugging to see what sws are registered and update/remove them.

SharedWorker() - Web APIs
name optional a domstring specifying an identifying name for the sharedworkerglobalscope representing the scope of the worker, which is mainly useful for debugging purposes.
... name: a domstring specifying an identifying name for the sharedworkerglobalscope representing the scope of the worker, which is mainly useful for debugging purposes.

URLSearchParams.set() - Web APIs
line #41: comment out this line to stop dumping the search parameters to the console (debug).
... 'use strict' function genurl(rexp, atext, bdebug=false){ let theurl theurl= new url('https://regexr.com') theurl.searchparams.set( 'expression', rexp.tostring() ) theurl.searchparams.set( 'tool', 'replace' ) theurl.searchparams.set( 'input', '\u2911\u20dc' )// ⤑⃜ theurl.searchparams.set( 'text', atext.join('\n') ) if( bdebug ){ // display the key/value pairs for(var pair of theurl.searchparams.entries()) { console.debug(pair[0] + ' = \'' + pair[1] + '\''); } console.debug(theurl) } return theurl } var url = genurl( /(^\s*\/\/|\s*[^:]\/\/).*\s*$|\s*\/\*(.|\n)+?\*\/\s*$/gm // sin...

WebGL constants - Web APIs
var debuginfo = gl.getextension('webgl_debug_renderer_info'); var vendor = gl.getparameter(debuginfo.unmasked_vendor_webgl); the webgl tutorial has more information, examples, and resources on how to get started with webgl.
... webgl_debug_renderer_info constant name value description unmasked_vendor_webgl 0x9245 passed to getparameter to get the vendor string of the graphics driver.

WebGL best practices - Web APIs
after too many errors (32 in firefox), webgl stops generating descriptive messages, which really hinders debugging.
... take advantage of universally supported webgl 1 extensions these webgl 1 extensions are universally supported: angle_instanced_arrays ext_blend_minmax oes_element_index_uint oes_standard_derivatives oes_vertex_array_object webgl_debug_renderer_info webgl_lose_context (see also: https://jdashg.github.io/misc/webgl/webgl-feature-levels.html) consider polyfilling these into webglrenderingcontext, like: https://github.com/jdashg/misc/blob/master/webgl/webgl-v1.1.js universally supported limits the minimum requirements for webgl are quite low.

window.dump() - Web APIs
notes a common use of dump() is to debug javascript.
...it is therefore advisable to either check this preference yourself or use a debugging preference of your own to make sure you don't send lots of debugging content to a user's console when they might not be interested in it at all.

CSS: Cascading Style Sheets
this module looks at the cascade and inheritance, all the selector types we have available, units, sizing, styling backgrounds and borders, debugging, and lots more.
...this is an invaluable debugging tool.

HTTP Index - HTTP
183 sourcemap http, http header, reference, response header, header the sourcemap http response header links generated code to a source map, enabling the browser to reconstruct the original source and present the reconstructed original in the debugger.
... 215 trace http, reference, trace method the http trace method performs a message loop-back test along the path to the target resource, providing a useful debugging mechanism.

An overview of HTTP - HTTP
this role is primarily performed by the web browser; other possibilities are programs used by engineers and web developers to debug their applications.
...session flow remains simple, allowing it to be investigated, and debugged with a simple http message monitor.

Memory Management - JavaScript
node.js node.js offers additional options and tools for configuring and debugging memory issues that may not be available for javascript executed within a browser environment.
... v8 engine flags the max amount of available heap memory can be increased with a flag: node --max-old-space-size=6000 index.js we can also expose the garbage collector for debugging memory issues using a flag and the chrome debugger: node --expose-gc --inspect index.js see also ibm article on "memory leak patterns in javascript" (2007) kangax article on how to register event handler and avoid memory leaks (2010) performance ...

Statements and declarations - JavaScript
others debugger invokes any available debugging functionality.
... if no debugging functionality is available, this statement has no effect.

XPath
xmlquire (formerly known as sketchpath) a graphical xpath builder/debugger(.net).
... xpath tester an online xpath builder/debugger.

Loading Content Scripts - Archive of obsolete content
this makes your code easier to maintain, secure, debug and review.

Content Processes - Archive of obsolete content
by only passing messages between add-on modules and content scripts, these problems can be avoided, making your add-on both easier to debug and to maintain.

context-menu - Archive of obsolete content
this makes your code easier to maintain, secure, debug and review.

page-worker - Archive of obsolete content
this makes your code easier to maintain, secure, debug and review.

panel - Archive of obsolete content
this makes your code easier to maintain, secure, debug and review.

widget - Archive of obsolete content
this makes your code easier to maintain, secure, debug and review.

/loader - Archive of obsolete content
id add-on debugging requires knowing which objects belong to which add-on.

Implementing the widget - Archive of obsolete content
you should see the widget in the add-on bar: left- and right-clicks should produce the appropriate debug output, and a left-click should also change the widget icon to signal that it is active.

Logging - Archive of obsolete content
the dom console object is useful for debugging javascript.

Modifying Web Pages Based on URL - Archive of obsolete content
this makes the code easier to maintain, debug, and review.

Modifying the Page Hosted by a Tab - Archive of obsolete content
this makes the code easier to maintain, debug, and review.

Bootstrapped extensions - Archive of obsolete content
add-on debugger from firefox 31 onwards, you can use the add-on debugger to debug bootstrapped add-ons.

Code snippets - Archive of obsolete content
downloading files code to download files, images, and to monitor download progress password manager code used to read and write passwords to/from the integrated password manager bookmarks code used to read and write bookmarks javascript debugger service code used to interact with the javascript debugger service svg general general information and utilities svg animation animate svg using javascript and smil svg interacting with script using javascript and dom events to create interactive svg embedding svg in html and xul using svg to enhance html or xul based markup xul widgets html in xul for rich tooltips dynamica...

Enhanced Extension Installation - Archive of obsolete content
making the database file format human readable would also help developers debug their installation problems.

Extension Versioning, Update and Compatibility - Archive of obsolete content
debugging and solving problems the update mechanism logs information to the console, and display various information which can help you to find problem.

Jetpack Processes - Archive of obsolete content
individual lines of the form //@line 1 "foo.js" can be used to specify filename and line number information for debugging purposes.

Migrating from Internal Linkage to Frozen Linkage - Archive of obsolete content
- #include "nsastring.h"- #include "nsstring.h"- #include "nsreadableutils.h"- #include "nsescape.h" + #include "nsstringapi.h" on windows, if you see the following error, you are including a header you shouldn't be: nsstringfwd.h(60) : fatal error c1001: internal compiler error to debug this error, make in the failing directory, adding the /showincludes directive to figure out what is being included incorrectly: make -c directory/that/failed os_cppflags=-showincludes the frozen string api is similar but not identical to the nonfrozen string api.

Adding windows and dialogs - Archive of obsolete content
it's ok to use this function if you're just debugging some problem and want to see if the program reaches a specific line of code, or to inspect the value of a variable, but your final extension should not have alert calls anywhere.

Connecting to Remote Content - Archive of obsolete content
http debugging when you start debugging http requests, you may find it hard to know exactly what data was sent, especially with post data.

List of Mozilla-Based Applications - Archive of obsolete content
ylizer css editor css editor css editor with built-in firebug-like diagnostics and gecko 1.8 preview sun java enterprise system server products uses nss sundial browser with advanced domain name technology based on firefox surfeasy private and secure web browsing sweet16 apple ii computer emulator uses spidermonkey as a scriptable debugger for software running in the emulator mozilla sunbird/mozilla lightning calendar tabpress authoring tool talend open studo data integration software seems to use xulrunner talking clipboard text to speech software read epub books, web pages, chm, pdf, ms word, rtf, rss feeds taskpool productivity telasocial ...

Source code directories overview - Archive of obsolete content
these include: cookies, irc, wallet, dom inspector, p3p, schema validation, spellchecker, transformiix, typeaheadfind, javascript debugger, xforms, etc.

ActiveX Control for Hosting Netscape Plug-ins in IE - Archive of obsolete content
build it it is quite simple to build the control locate the pluginhostctrl directory: open pluginhostctrl.dsp build "win32 debug" or another target open some of the test files under pluginhostctrl\tests in internet explorer to verify the control has built and registered correctly.

Installing Dehydra - Archive of obsolete content
cd $home hg clone http://hg.mozilla.org/mozilla-central/ cd mozilla-central hg update aurora_base_20110705 cd js/src autoconf-2.13 mkdir $home/obj-js cd $home/obj-js $home/mozilla-central/js/src/configure --enable-optimize --disable-debug make it has to be checked whether later/newer branches (like aurora_base_20120131) are working, too.

Extension Frequently Asked Questions - Archive of obsolete content
before asking for help, be sure to set the debugging prefs and check the error console for related messages.

JavaScript Client API - Archive of obsolete content
testing and debugging your engine set observers in the tracker to tell when your datatype changes, after which the score needs to be set.

Jetpack Snippets - Archive of obsolete content
using firebug lite in a slidebar jetpack.future.import("slidebar");jetpack.slidebar.append({ html: <html><head></head><body> <p>some slidbar you want to debug</p> <a href="javascript:console.log('hello!')">test</a> <script><![cdata[ //firebug lite bookmarklet code: var firebug=document.createelement('script'); firebug.setattribute('src','http://getfirebug.com/releases/lite/1.2/firebug-lite-compressed.js'); document.body.appendchild(firebug); (function(){if(...

Modularization techniques - Archive of obsolete content
in debug builds, these macros provide useful reference counting logs.

Mozilla Application Framework - Archive of obsolete content
tools venkman a javascript debugger with support for breakpoints, conditional breakpoints, local variable inspection, watch variables, single step, stop on error, profile data collection, report generation, code reformatting (pretty printing), and more.

LIR - Archive of obsolete content
r allocate stack space (result is an address) 6 reti void return an int 7 retq void 64 bit return a quad 8 retd void return a double 9 livei void extend live range of an int 10 liveq void 64 bit extend live range of a quad 11 lived void extend live range of a double 12 file void source filename for debug symbols 13 line void source line number for debug symbols 14 comment void a comment shown, on its own line, in lir dumps 15 not in use load 16 not in use 17 ldc2i integer load char and sign-extend to an int 18 lds2i integer load short and sign-extend to an int 19 lduc2ui integer load unsign...

Plug-n-Hack - Archive of obsolete content
or example, to configure a browser to use an intercepting proxy that can handle https traffic, the user must typically: configure their browser to proxy via the tool configure the tool to proxy via their corporate proxy import the tool’s ssl certificate into their browser if any of these steps are carried out incorrectly then the browser will typically fail to connect to any website – debugging such problems can be frustrating and time-consuming.

Build - Archive of obsolete content
the contents of the file should look something like this : mk_add_options moz_co_project=xulrunner mk_add_options moz_objdir=@topsrcdir@/mozilla-obj ac_add_options --enable-application=xulrunner ac_add_options --disable-debug ac_add_options --enable-optimize ac_add_options --disable-tests ac_add_options --disable-javaxpcom build xulrunner : make -f client.mk build once the build is done, there will be a directory called mozilla-obj.

Priority Content - Archive of obsolete content
started: using mozilla in testing and debugging web sites original: using mozilla in testing and debugging web sites wiki location: using mozilla in testing and debugging web sites migrators: serge k.

Hacking wiki - Archive of obsolete content
random tips you can set the file to log by putting something like this in your localsettings.php: $wgdebuglogfile = 'c:\\123'; you can then use wfdebug() function to write to the log.

Frequently Asked Questions - Archive of obsolete content
this is an xml debugging message to help xml authors correct errors in their xml documents.

Static Analysis for Windows Code under Linux - Archive of obsolete content
ac_add_options --enable-debug ac_add_options --disable-optimize ac_add_options --disable-tests ac_add_options --disable-embedding-tests ac_add_options --disable-installer ac_add_options --disable-accessibility ac_add_options --disable-vista-sdk-requirements ac_add_options --disable-updater #change this to where your libidl-config file locate.

Table Cellmap - Archive of obsolete content
enabling the debug code at the function entrance and exit gives a quite complete picture of the cellmap structure.

Abc Assembler Tests - Archive of obsolete content
y summary end():void - test section finished compare_stricteq(name:string, expected:*, actual:*):void - compare the results of a testcase where name is the testcase name compare_typeerror(name:string, expected:*, actual:*):void - special function for comparing typeerrors (runtimeerrors) - will only compare the first 22 chars of expected and actual so that test can be run in release and releasedebugger configurations.

Actionscript Acceptance Tests - Archive of obsolete content
the first line must contain the expected error (without the extra debugger information).

Cmdline tests - Archive of obsolete content
two use cases for the cmdline testsuite: use case 1: test the interactive cmdline debugger test contents: start avmshell -d test.abc, set breakpoint on a line, show local variable value, quit from cmdutils import * def run(): r=runtestlib() r.run_test( 'debugger locals', '%s -d testdata/debug.abc'%r.avmrd, input='break 53\ncontinue\nnext\ninfo locals\nnext\ninfo locals\nquit\n', expectedout=['local1 = undefined','local2 = 10','local2 = 15'] ) use case 2: test -memstats retur...

Tamarin Acceptance Testing - Archive of obsolete content
successfully build release and debug versions of the shell with the debugger enabled [info] successfully run the following test suites: acceptance test suite [info] self tests [info] submit a sandbox build request to test against platforms that you may not have locally [info] available tamarin acceptance test suites actionscript acceptance tests: actionscript acceptance tests running tamarin acceptance tests abc assembler tests cmdline tests performance tests actionscript performance tests running tamarin performance tests built-in self tests ...

Tamarin Build System Documentation - Archive of obsolete content
the acceptance tests are the majority and are run on all shells (release, release-debugger, debug, debug-debugger).

Video presentations - Archive of obsolete content
(as quicktime; 138 mb and 132 mb) developing mozilla these presentations cover various aspects of the process of working on the mozilla project, including building, testing, and debugging.

Learn XPI Installer Scripting by Example - Archive of obsolete content
installation logging logging is an important feature of the xpinstall api that can help you streamline and debug your installations.

Adding Event Handlers - Archive of obsolete content
you can also change the preference javascript.options.strict for debugging.

Introduction - Archive of obsolete content
the time required to compile and debug can be lengthy.

Manifest Files - Archive of obsolete content
if you are using a debug build of mozilla, some info will be printed to the terminal when starting up indicating what chrome applications are being checked.

XUL accessibility tool - Archive of obsolete content
improve tool along the way add checking tool to dom inspector or other popular xul debugging tools.

xulauncher - Archive of obsolete content
ko] minversion=1.8 maxversion=1.9 ">$xulappini # create chrome.manifest file ############################################################################## echo " content $xulname file:$xulname/ ">$xulmanifest # create prefs.js file ############################################################################## echo " pref(\"toolkit.defaultchromeuri\", \"chrome://$xulname/content/$xulfile\"); /* debugging prefs */ pref(\"browser.dom.window.dump.enabled\", true); pref(\"javascript.options.showinconsole\", true); pref(\"javascript.options.strict\", true); pref(\"nglayout.debug.disable_xul_cache\", true); pref(\"nglayout.debug.disable_xul_fastload\", true); ">$xulprefs # copy xul file to right location and run it ############################################################################## cp $...

XULRunner - Archive of obsolete content
debug documentation steps to configure venkman to debug your app xulrunner guide a fairly complete, but outdated, introduction and tutorial for xulrunner which collates much of the documentation found here.

XUL Explorer - Archive of obsolete content
a xul validator and the error console are both available to help debug problems.

Mozilla release FAQ - Archive of obsolete content
please send stats to me in the following format: cpu/mhz, architecture, ram, disk type, os version, compiler version, build type, tree date -- build time example: 21164/533, alpha, 512m edo, ultra2 scsi, linux kernel 2.2.11, gcc 2.95, non-debug, 19 august 1999 cvs -- 25 minutes how do i run the binary on unix?

2006-10-26 - Archive of obsolete content
debug minefield on intel mac an inqury about how to debug minefield on an intel mac.

2006-10-27 - Archive of obsolete content
debug minefield on intel mac an inqury about how to debug minefield on an intel mac.

2006-11-17 - Archive of obsolete content
two questions: (1) launching a separate intance of firefox.exe, and (2) programmatically closing a window user has two questions about using adobe flex builder debugger in firefox 2.0.

2006-10-27 - Archive of obsolete content
./configure --prefix=/export/home/alex/thunderbird --enable-application=browser --disable-tests --disable-debug -disable-auto-deps --disable-freetype2 -enable-official-branding --enable-default-toolkit=gtk2 --enable-optimize=-xo5 --enable-static --disable-shared --enable-xft --enable-svg the build tools that he used to build firefox 2 are listed in his posting along with the error that he receives when he tries to build it.

2006-11-17 - Archive of obsolete content
site not loading with seamonkey a user built seamonkey in debug mode and is currently receiving a "bad request" error on some websites.

2006-11-17 - Archive of obsolete content
calendar xpcom component discussion about a debug error of additem function from calicalendar.

Plugins - Archive of obsolete content
logging and debugging for multi-process plugins how to create a plugin log to aid in debugging problems with multi-process plugins.

Table Reflow Internals - Archive of obsolete content
table reflow example <table width=300> <tr> <td>foo</td> <td>bar zap</td> </tr> </table> key: r = reflow reason, 0 (initial), 2 (resize) a = avail w, h c = computed w, h d = desired w, h me = max elem w debugging frame reflow gives instructions for turning this on: tblo 030176cc r=0 a=8940,uc c=0,0 cnt=429 tbl 030178c4 r=0 a=8940,uc c=4470,uc cnt=430 rowg 03017a7c r=0 a=uc,uc c=uc,uc cnt=431 row 03017c08 r=0 a=uc,uc c=uc,uc cnt=432 cell 03017da8 r=0 a=uc,uc c=uc,uc cnt=433 block 03017e08 r=0 a=uc,uc c=uc,uc cnt=434 block 03017e08 d=870,300 me=480 cell 03017da8 d=...

Common Firefox theme issues and solutions - Archive of obsolete content
debugger debugger toolbar buttons are missing icons on the debugger (tools > web developer > debugger) the toolbar buttons are missing their icons.

Scratchpad - Archive of obsolete content
to do this check "enable chrome and add-on debugging" in the developer tool settings.

References - Archive of obsolete content
from matt kruse debugging html and css is a well designed website explaining well the how, why and where of html validation, css validation and debugging tools.

Microsoft JavaScript extensions - Archive of obsolete content
objects activexobject debug enumerator vbarray functions getobject scriptengine scriptenginebuildversion scriptenginemajorversion scriptengineminorversion statements @cc-on @if @set other date.getvardate() error.description error.number error.stacktracelimit ...

Back to the Server: Server-Side JavaScript On The Rise - Archive of obsolete content
for debugging, jaxer will also send database errors to the client if you want.

Standards-Compliant Authoring Tools - Archive of obsolete content
macromedia™ dreamweaver™ cs6 style master and layout master by western civilisation some caveats: it appears that tools currently available from namo generate ie-specific or netscape 4-specific code that may require extra debugging for compatibility with standards-based browsers.

Choosing Standards Compliance Over Proprietary Practices - Archive of obsolete content
pilot had a highly-integrated debugging tool called co-pilot that allowed the xerox development organization to quickly and easily debug issues.

RDF in Mozilla FAQ - Archive of obsolete content
this is useful for debugging generated rdf/xml that may change over time.

Anatomy of a video game - Game development
note: changing how your main loop deals with time is a debugging nightmare, everywhere.

Index - Game development
39 tools for game development games, gecko, guide, javascript on this page you can find links to our game development tools articles, which eventually aims to cover frameworks, compilers, and debugging tools.

Game distribution - Game development
plus, it is usually easier to build and test the game first on desktop, and then move on to debugging mobile.

Bounding volume collision detection with THREE.js - Game development
we can easily debug collisions by rendering the meshes that boxhelper creates.

Desktop gamepad controls - Game development
received values are assigned to the proper objects and returns the pressed info for debugging purposes.

Mobile touch controls - Game development
hauling in phaser, if enabled, will work out of the box — you don't have to set the position of the sprite yourself manually, so you could leave the ondragstart() function empty, or place some debug output to see if it's working correctly.

Implementing controls using the Gamepad API - Game development
if(c.buttons[b].pressed) { pressed.push(gamepadapi.buttons[b]); } } } // loop through axes and push their values to the array var axes = []; if(c.axes) { for(var a=0,x=c.axes.length; a<x; a++) { axes.push(c.axes[a].tofixed(2)); } } // assign received values gamepadapi.axesstatus = axes; gamepadapi.buttonsstatus = pressed; // return buttons for debugging purposes return pressed; }, on every frame, update() saves buttons pressed during the previous frame to the buttonscache array and takes fresh ones from the gamepadapi.controller object.

2D breakout game using pure JavaScript - Game development
frameworks speed up development time and help take care of boring parts of the game, but if something is not working as expected, you can always try to debug that or just write your own solutions in pure javascript.

Visual typescript game engine - Game development
luanch debugger configuration comes with this project.

Plug-in Development Overview - Gecko Plugin API Reference
test your plug-in and debug as necessary.

First-class Function - MDN Web Docs Glossary: Definitions of Web-related terms
naming it will be helpful when debugging your code.

IDE - MDN Web Docs Glossary: Definitions of Web-related terms
an ide normally consists of a source code editor, build automation tools and a debugger.

Symbol - MDN Web Docs Glossary: Definitions of Web-related terms
symbol can have an optional description, but for debugging purposes only.

MDN Web Docs Glossary: Definitions of Web-related terms
world wide web wrapper x xforms xhr (xmlhttprequest) xhtml xinclude xlink xml xpath xquery xslt other 404 502 alpn at-rule attack byte-order mark character set client cryptosystem debug digital signature execution flex-direction glsl interface library memory management routers self-executing anonymous function stylesheet vector image ...

Backgrounds and borders - Learn web development
us overview: building blocks next in this module cascade and inheritance css selectors type, class, and id selectors attribute selectors pseudo-classes and pseudo-elements combinators the box model backgrounds and borders handling different text directions overflowing content values and units sizing items in css images, media, and form elements styling tables debugging css organizing your css ...

Handling different text directions - Learn web development
us overview: building blocks next in this module cascade and inheritance css selectors type, class, and id selectors attribute selectors pseudo-classes and pseudo-elements combinators the box model backgrounds and borders handling different text directions overflowing content values and units sizing items in css images, media, and form elements styling tables debugging css organizing your css ...

Images, media, and form elements - Learn web development
previous overview: building blocks next in this module cascade and inheritance css selectors type, class, and id selectors attribute selectors pseudo-classes and pseudo-elements combinators the box model backgrounds and borders handling different text directions overflowing content values and units sizing items in css images, media, and form elements styling tables debugging css organizing your css ...

Organizing your CSS - Learn web development
previous overview: building blocks in this module cascade and inheritance css selectors type, class, and id selectors attribute selectors pseudo-classes and pseudo-elements combinators the box model backgrounds and borders handling different text directions overflowing content values and units sizing items in css images, media, and form elements styling tables debugging css organizing your css ...

Overflowing content - Learn web development
us overview: building blocks next in this module cascade and inheritance css selectors type, class, and id selectors attribute selectors pseudo-classes and pseudo-elements combinators the box model backgrounds and borders handling different text directions overflowing content values and units sizing items in css images, media, and form elements styling tables debugging css organizing your css ...

Attribute selectors - Learn web development
us overview: building blocks next in this module cascade and inheritance css selectors type, class, and id selectors attribute selectors pseudo-classes and pseudo-elements combinators the box model backgrounds and borders handling different text directions overflowing content values and units sizing items in css images, media, and form elements styling tables debugging css organizing your css ...

Combinators - Learn web development
us overview: building blocks next in this module cascade and inheritance css selectors type, class, and id selectors attribute selectors pseudo-classes and pseudo-elements combinators the box model backgrounds and borders handling different text directions overflowing content values and units sizing items in css images, media, and form elements styling tables debugging css organizing your css ...

Pseudo-classes and pseudo-elements - Learn web development
us overview: building blocks next in this module cascade and inheritance css selectors type, class, and id selectors attribute selectors pseudo-classes and pseudo-elements combinators the box model backgrounds and borders handling different text directions overflowing content values and units sizing items in css images, media, and form elements styling tables debugging css organizing your css ...

Type, class, and ID selectors - Learn web development
us overview: building blocks next in this module cascade and inheritance css selectors type, class, and id selectors attribute selectors pseudo-classes and pseudo-elements combinators the box model backgrounds and borders handling different text directions overflowing content values and units sizing items in css images, media, and form elements styling tables debugging css organizing your css ...

CSS selectors - Learn web development
or h1 ~ p general sibling in this module cascade and inheritance css selectors type, class, and id selectors attribute selectors pseudo-classes and pseudo-elements combinators the box model backgrounds and borders handling different text directions overflowing content values and units sizing items in css images, media, and form elements styling tables debugging css organizing your css ...

Sizing items in CSS - Learn web development
us overview: building blocks next in this module cascade and inheritance css selectors type, class, and id selectors attribute selectors pseudo-classes and pseudo-elements combinators the box model backgrounds and borders handling different text directions overflowing content values and units sizing items in css images, media, and form elements styling tables debugging css organizing your css ...

The box model - Learn web development
us overview: building blocks next in this module cascade and inheritance css selectors type, class, and id selectors attribute selectors pseudo-classes and pseudo-elements combinators the box model backgrounds and borders handling different text directions overflowing content values and units sizing items in css images, media, and form elements styling tables debugging css organizing your css ...

CSS values and units - Learn web development
us overview: building blocks next in this module cascade and inheritance css selectors type, class, and id selectors attribute selectors pseudo-classes and pseudo-elements combinators the box model backgrounds and borders handling different text directions overflowing content values and units sizing items in css images, media, and form elements styling tables debugging css organizing your css ...

Introduction to CSS layout - Learn web development
this worked at the time, but it has many problems — table layouts are inflexible, very heavy on markup, difficult to debug, and semantically wrong (e.g., screen reader users have problems navigating table layouts).

CSS FAQ - Learn web development
you can use dom inspector's css style rules view to debug problems of this kind, but the most frequent instances of ignored style rules are listed below.

Use CSS to solve common problems - Learn web development
common use cases basics how to apply css to the dom how to use whitespace in css how to write comments in css how to select elements via element name, class or id how to select elements via attribute name and content how to use pseudo-classes how to use pseudo-elements how to apply multiple selectors to the same rule how to specify colors in css how to debug css in the browser css and text how to style text how to customize a list of elements how to style links how to add shadows to text boxes and layouts how to size css boxes how to control overflowing content how to control the part of a css box that the background is drawn under how do i define inline, block, and inline-block?

Learn to style HTML using CSS - Learn web development
this module looks at the cascade and inheritance, all the selector types we have available, units, sizing, styling backgrounds and borders, debugging, and lots more.

Publishing your website - Learn web development
generally speaking, these tools are relatively easy, great for learning, good for sharing code (for example, if you want to share a technique with or ask for debugging help from colleagues in a different office), and free (for basic features).

The web and web standards - Learn web development
examples include: the developer tools inside modern browsers that can be used to debug your code.

Advanced text formatting - Learn web development
metadata in html html text fundamentals creating hyperlinks advanced text formatting document and website structure debugging html marking up a letter structuring a page of content ...

Creating hyperlinks - Learn web development
metadata in html html text fundamentals creating hyperlinks advanced text formatting document and website structure debugging html marking up a letter structuring a page of content ...

Document and website structure - Learn web development
in the last article of this module, we'll study how to debug html.

HTML text fundamentals - Learn web development
metadata in html html text fundamentals creating hyperlinks advanced text formatting document and website structure debugging html marking up a letter structuring a page of content ...

Marking up a letter - Learn web development
metadata in html html text fundamentals creating hyperlinks advanced text formatting document and website structure debugging html marking up a letter structuring a page of content ...

Structuring a page of content - Learn web development
metadata in html html text fundamentals creating hyperlinks advanced text formatting document and website structure debugging html marking up a letter structuring a page of content ...

What’s in the head? Metadata in HTML - Learn web development
metadata in html html text fundamentals creating hyperlinks advanced text formatting document and website structure debugging html marking up a letter structuring a page of content ...

Introduction to HTML - Learn web development
debugging html writing html is fine, but what if something goes wrong, and you can't work out where the error in the code is?

Responsive images - Learn web development
when testing it with a mobile browser, you can use tools like firefox's about:debugging page to inspect the page loaded on the mobile using the desktop developer tools.

HTML table basics - Learn web development
this can result in the code being harder to write, maintain, and debug.

Storing the information you need — Variables - Learn web development
there are many reasons why you'd want to do this, from security (if a third party script changed such values it could cause problems) to debugging and code comprehension (it is harder to accidentally change values that shouldn't be changed and mess things up).

Inheritance in JavaScript - Learn web development
too much inheritance can lead to endless confusion, and endless pain when you try to debug such code.

Server-side web frameworks - Learn web development
it contains a development server and debugger, and includes support for jinja2 templating, secure cookies, unit testing, and restful request dispatching.

Dynamic behavior in Svelte: working with variables and props - Learn web development
basic debugging with console.log() and reactive statements.

Creating our first Vue component - Learn web development
in part, components editing props can make debugging a challenge.

Introduction to automated testing - Learn web development
devtools — allows you to use your browser's devtools to directly debug or manipulate the page being shown in the test browser.

Setting up your own test automation environment - Learn web development
tents: const webdriver = require('selenium-webdriver'), by = webdriver.by, until = webdriver.until; // input capabilities let capabilities = { 'browsername' : 'firefox', 'browser_version' : '56.0 beta', 'os' : 'os x', 'os_version' : 'sierra', 'resolution' : '1280x1024', 'browserstack.user' : 'your-user-name', 'browserstack.key' : 'your-access-key', 'browserstack.debug' : 'true', 'build' : 'first build' }; let driver = new webdriver.builder().

Tools and testing - Learn web development
for example, you'll need to know the fundamentals of these languages before you start debugging problems in complex web code, making effective use of javascript frameworks, or writing tests and running them against your code using test runners.

Embedding API for Accessibility
be aware that in debug builds, this can cause a great number of assertions (bug 71598) to use prefs in embedding, use something like the following code: #include "nsipref.h"; nsresult rv; nscomptr<nsipref> prefs(do_getservice(ns_pref_contractid, &rv)); prefs->setboolpref("bool.pref.name", pr_true /* or pr_false */); prefs->setintpref("int.pref.name", newvalue); prefs->setcharpref("string.pref.name", newcharstarval...

Browser chrome tests
for example, to run the tests in browser/base/content/test the command would be: ./mach mochitest -f browser browser/base/content/test/ or without mach test_path=<path_to_the_tests> make -c <objdir> mochitest-browser-chrome to run tests in debugger the following should work ./mach mochitest -f browser --debugger gdb browser/base/content/test/ run ./mach help mochitest-browser for more options.

Building SpiderMonkey with UBSan
f213 mkdir $1 cd $1 llvm_root="$home/llvm" sanflag="-fsanitize=undefined -fno-sanitize=alignment,float-cast-overflow,float-divide-by-zero,vptr -dxmalloc=myxmalloc" \ cc="$llvm_root/build/release+asserts/bin/clang" \ cxx="$llvm_root/build/release+asserts/bin/clang++" \ cflags="$sanflag" \ cxxflags="$sanflag" \ moz_llvm_hacks=1 \ ../configure --enable-debug --disable-optimize make -j 8 fi 3.

Chrome registration
global classic/1.0 jar:classic.jar!/skin/classic/global/ override chrome://global/content/neterror.xhtml jar:embedder.jar!/global/content/neterror.xhtml content inspector jar:inspector.jar!/content/inspector/ instructions supported in bootstrapped add-ons the following instructions are supported in bootstrapped extensions: manifest content locale skin override debugging a chrome manifest file the chrome list extension shows all registered chrome.

Creating reftest-based unit tests
if you built a debug version of the browser, there can be a lot of extra console output.

Makefile - variables
dest=$(moz_objdir)/$project moz_current_project moz_debug moz_enable_xremote moz_feeds moz_help_viewer moz_native_nspr moz_metro moz_pkg_mainfest moz_preflight_all moz_rdf moz_toolkit_search moz_url_classifier ...

Old Thunderbird build
for example, to create a debug build instead of a release build, that file would contain: ac_add_options --enable-debug for more on configuration options, see the page configuring build options.

Simple Instantbird build
for example, to create a debug build instead of a release build, that file would contain: ac_add_options --enable-debug for more on configuration options, see the page configuring build options.

Simple Thunderbird build
for example, to create a debug build instead of a release build, that file would also contain the line: ac_add_options --enable-debug each of these ac_add_options entries needs to be on its own line.

The Firefox codebase: CSS Guidelines
using variables use the variable according to its naming do this: xul|tab:hover { background-color: var(--in-content-box-background-hover); } not this: #certificateerrordebuginformation { background-color: var(--in-content-box-background-hover); } localization text direction for margins, padding and borders, use inline-start/inline-end rather than left/right.

Reviewer Checklist
remove debug logging that is not needed in production.

Developer guide
debugging find helpful tips and guides for debugging mozilla code.

Storage access policy: Block cookies from trackers
debugging we encourage site owners to test their sites, particularly those that rely on third-party content integrations.

Tracking Protection
note that with firefox for android, you can access console output using the remote debugger.

Firefox and the "about" protocol
about:crashes lists all crashes, which happened during the runtime of firefox (in case the user enabled the crash reporter) about:credits lists all contributors to the firefox project about:debugging switches to the developer tools debugging page, which allows you to debug add-ons, tabs and service workers about:devtools summarizes the developer tools and provides links to documentation for each tool about:downloads displays all downloads done within firefox about:home start page of firefox when opening a new window about:license displays...

Http.jsm
logger an object that implements the debug and log methods (e.g.

JavaScript OS.Constants
debug set to true on debug build configurations, non-existent otherwise.

Examples
sful and reason was = "' + asuccessreason + '"'); }, function(arejectreason) { alert('mypromise failed for reason = "' + uneval(arejectreason) + '"'); } ); function myuserdefinedpromise() { return 'i didnt do a promise.resolve so this will not understand that mypromise is a promise'; } // creates this error: /* exception: mypromise.then is not a function @scratchpad/5:8:1 wca_evalwithdebugger@resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/devtools/server/actors/webconsole.js:1069:7 wca_onevaluatejs@resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/devtools/server/actors/webconsole.js:734:9 dsc_onpacket@resource://gre/modules/commonjs/toolkit/loader.js -> resource://gre/modules/devtools/server/main.js:1098:9 ldt_send/<@resource:...

source-editor.jsm
note: implementing actual support for debugger features such as breakpoints is up to you.

Release phase
if you don't see this message, try running the same command in a more verbose mode (with the debugging information): $ ssh -vvv hg.mozilla.org this should tell you why your connection is not succeeding.

Mozilla Framework Based on Templates (MFBT)
(this header will likely be further split up so that its functionality is less grab-bag.) debugging assertions.h provides assertion macros in implementing runtime assertions and compile-time assertions.

Mozilla DOM Hacking Guide
the first argument passed to ns_define_classinfo_data_with_name, _class, is used for debug purposes.

GPU performance
see also debugging with pix.

Gecko Profiler FAQ
in that case, the gecko profiler is the wrong tool to debug this.

Profiling with Xperf
ac_add_options --enable-debug-symbols this gives us symbols.

Profiling with the Gecko Profiler and Local Symbols on Windows
generate the breakpad symbol files by running ./mach buildsymbols: https://developer.mozilla.org/en/building_firefox_with_debug_symbols#breakpad_symbol_files this will have created symbols under $objdir/dist/ , named after the binary name, architecture and version, so something like "firefox-40.0a1.en-us-win32.crashreporter-symbols.zip" point talos to this zipfile by passing its path to the --symbolspath flag.

Preference reference
the old behavior can be restored by setting the preference mail.tabs.drawintitlebar to false.nglayout.debug.disable xul fastloadthe preference nglayout.debug.disable_xul_fastload controls whether or not xul fastload is used.nglayout.debug.disable_xul_cacheto improve performance, mozilla caches chrome xul documents the first time they load for faster loading later.

Crash reporting
see also understanding crash reports a guide to searching crash reports crash-stats crash pings (telemetry) and crash reports (socorro/crash stats) building firefox with debug symbols environment variables affecting crash reporting in-code documentation crash reporter crash manager crash ping ...

Firefox Sync
there are also some notes in a google document (that we really must move to its own wiki page) there's also information available to help debug and diagnose android sync issues.

Nonblocking IO In NSPR
these constraints are enforced in the debug nspr library by assertions.

NSPR LOG MODULES
level is a numeric value between 0 and 5, with the values having the following meanings: 0 = pr_log_none: nothing should be logged 1 = pr_log_always: important; intended to always be logged 2 = pr_log_error: errors 3 = pr_log_warning: warnings 4 = pr_log_debug: debug messages, notices 5: everything!

PRLogModuleLevel
syntax #include <prlog.h> typedef enum prlogmodulelevel { pr_log_none = 0, pr_log_always = 1, pr_log_error = 2, pr_log_warning = 3, pr_log_debug = 4, pr_log_notice = pr_log_debug, pr_log_warn = pr_log_warning, pr_log_min = pr_log_debug, pr_log_max = pr_log_debug } prlogmodulelevel; ...

PR_Abort
syntax #include <prinit.h> void pr_abort(void); description pr_abort results in a core file and a call to the debugger or equivalent, in addition to causing the entire process to stop.

PR_LOG
possible values are: pr_log_none = 0 pr_log_always = 1 pr_log_error = 2 pr_log_warning = 3 pr_log_debug = 4 pr_log_notice = pr_log_debug pr_log_warn = pr_log_warning pr_log_min = pr_log_debug pr_log_max = pr_log_debug _args a variable length argument list, as if to printf.

PR_LOG_TEST
possible values are: pr_log_none = 0 pr_log_always = 1 pr_log_error = 2 pr_log_warning = 3 pr_log_debug = 4 pr_log_notice = pr_log_debug pr_log_warn = pr_log_warning pr_log_min = pr_log_debug pr_log_max = pr_log_debug returns pr_true when logging is enabled for the given module and level, otherwise pr_false.

Running NSPR tests
to run the test suite, run the shell script mozilla/nsprpub/pr/tests/runtests.sh in the directory where the test program binaries reside, for example, cvs -q co -r nspr_4_6_6_rtm mozilla/nsprpub mkdir linux.debug cd linux.debug ../mozilla/nsprpub/configure gmake cd pr/tests gmake ../../../mozilla/nsprpub/pr/tests/runtests.sh the output of the test suite looks like this: nspr test results - tests begin mon mar 12 11:44:41 pdt 2007 nspr_test_logfile /dev/null test result accept passed acceptread passed accept...

NSPR
opensuse linux: install one or more of the following via yast or zypper : mozilla-nspr : binary libraries for your platform mozilla-nspr-32bit : binary libraries needed to run 32-bit programs on a 64-bit os mozilla-nspr-devel : files needed (in addition to the above libraries) to compile programs using nspr mozilla-nspr-debuginfo : debug information (including build symbols) for package mozilla-nspr mozilla-nspr-debuginfo-32bit : debug information (including build symbols) for package mozilla-nspr-32bit mozilla-nspr-debugsource : debug sources for all of the above community view mozilla forums...

NSS 3.12.4 release notes
[[@isspace - secmod_argisblank - secmod_arghasblanks - secmod_formatpair - secmod_mknewmodulespec] bug 498509: produce debuggable optimized builds for mozilla on macosx bug 498511: produce debuggable optimized nss builds for mozilla on linux bug 499385: drbg reseed function needs to be tested on post bug 499825: utilrename.h is missing from solaris packages bug 502961: allocator mismatch in pk11mode bug 502965: allocator mismatch in sdrtest bug 502972: another allocator mismatch in sdrtest bug 504398: pkix_pl_aiamgr_ge...

NSS 3.46 release notes
en possible for delegated credentials bug 1493916 - fix ppc64 inline assembler for clang bug 1561588 - remove -wmaybe-uninitialized warning in p7env.c bug 1561548 - remove -wmaybe-uninitialized warning in pkix_pl_ldapdefaultclient.c bug 1512605 - incorrect alert description after unencrypted finished msg bug 1564715 - read /proc/cpuinfo when at_hwcap2 returns 0 bug 1532194 - remove or fix -ddebug_$user from make builds bug 1565577 - visual studio's cl.exe -?

NSS 3.47 release notes
267894 - allow per-socket run-time ordering of the cipher suites presented in clienthello bug 1570501 - add cmac to freebl and pkcs #11 libraries bugs fixed in nss 3.47 bug 1459141 - make softoken cbc padding removal constant time bug 1589120 - more cbc padding tests bug 1465613 - add ability to distrust certificates issued after a certain date for a specified root cert bug 1588557 - bad debug statement in tls13con.c bug 1579060 - mozilla::pkix tag definitions for issueruniqueid and subjectuniqueid shouldn't have the constructed bit set bug 1583068 - nss 3.47 should pick up fix from bug 1575821 (nspr 4.23) bug 1152625 - support aes hw acceleration on armv8 bug 1549225 - disable dsa signature schemes for tls 1.3 bug 1586947 - pk11_importandreturnprivatekey does not store nickname f...

NSS Tools sslstrength
synopsis 1) sslstrength ciphers 2) sslstrength hostname[:port] [ciphers=xyz] [debug] [verbose] [policy=export|domestic] description the first form simple lists out the possible ciphers.

Overview of NSS
complete software development kit in addition to libraries and apis, nss provides security tools required for debugging, diagnostics, certificate and key management, cryptography module management, and other development tasks.

Sample manual installation
for example, <obj-dir> for a debug build of nss on the x86 platform with a linux kernel version 2.6 with glibc would be: linux2.6_x86_glibc_pth_dbg.obj from these directories, you can copy the files to any system (or other) directory.

NSS tools : pk12util
-v enable debug logging when importing.

gtstd.html
in addition, you must use the following compiler flags: solaris flags: -c -o -kpic -dsvr4 -dsysv -d__svr4 -d__svr4__ -dsolaris -d_reentrant -dsolaris2_5 -d_svid_gettod -dxp_unix -udebug -dndebug windows nt flags: -c -o2 -md -w3 -nologo -d_x86_ -gt -dwinnt -dxp_pc -udebug -u_debug -dndebug -dwin32 -d_windows ...

NSS troubleshooting
debugging tips, how to enable tracing of the various modules, etc.

NSS Tools pk12util
-h tokenname specify the name of the token to import into or export from -v enable debug logging when importing -k slotpasswordfile specify the text file containing the slot's password -k slotpassword specify a slot's password -w p12filepasswordfile specify the text file containing the pkcs 12 file's password -w p12filepassword specify the pkcs 12 file's password -c key-cipher specify the key encryption algorithm -c certcipher specify the pfx encryption algorithm -m...

NSS Tools sslstrength
synopsis 1) sslstrength ciphers 2) sslstrength hostname[:port] [ciphers=xyz] [debug] [verbose] [policy=export|domestic] description the first form simple lists out the possible ciphers.

NSS tools : pk12util
-v enable debug logging when importing.

NSS tools : signtool
retaining the temporary directories can be an aid to debugging.

Network Security Services
nss tools tools for developing, debugging, and managing applications that use nss.

Installing Pork
riting-and-analysis/pork/ cd pork hg clone http://hg.mozilla.org/rewriting-and-analysis/elsa ./configure make building mozilla with mcpp to build mozilla with mcpp to generate annotated .ii files, use the following configure command: ac_cv_visibility_hidden=no cc="gcc34 -save-temps -wp,-w0,-k" cxx="g++ -save-temps -wp,-w0,-k" cppflags=-dns_disable_literal_template $srcdir/configure --enable-debug --disable-optimize --disable-accessibility --enable-application=browser --disable-crashreporter building will probably require disabling warnings_as_errors: make warnings_as_errors= "-wp,-w0,-k" are options that get passed to mcpp.

Renaming With Pork
--dry-run is helpful for debugging filterdiff -x \*/smbase/\* /tmp/string.diff |sed 's/.home.tglek.tmp.//' | patch -p1 --dry-run ...

Rhino documentation
javascript debugger debugging scripts running in rhino.

Rhino license
license for portions of the rhino debugger additionally, some files (currently the contents of toolsrc/org/mozilla/javascript/tools/debugger/treetable/) are available under the following license: * copyright 1997, 1998 sun microsystems, inc.

Rhino overview
rhino contains all the features of javascript 1.7 allows direct scripting of java a javascript shell for executing javascript scripts a javascript compiler to transform javascript source files into java class files a javascript debugger for scripts executed with rhino language the javascript language itself is standardized by standard ecma-262 ecmascript: a general purpose, cross-platform programming language.

Rhino scopes and contexts
such bugs are hard to debug and to remove a possibility for them to occur one can seal the shared scope and all its objects.

How to embed the JavaScript engine
here are sample mac and linux command lines (where <objdir> is the directory where spidermonkey was built): # if you're using debug build of spidermonkey, you need -ddebug in addition to the command below.

JS::CallArgs
(if you're compiling against a debug build of spidermonkey, these methods will assert to aid debugging.) if the method you're implementing succeeds by returning true, you *must* set this.

JS::CompileOptions
the following are used in js shell: "js shell file" "js shell interactive" "js shell load" "js shell evaluate" "js shell run" "js shell disfile" "js shell compfile" "js shell parse" "js shell syntaxparse" "js shell offthreadcompilescript" and the following are used in self-hosted code and debugger: "self-hosted" "debugger eval" introductionlineno unsigned line number in the source code which introduces this source code.

JSFastNative
however, it causes the function not to appear on the stack in javascript debuggers.

JSNative
this causes the function not to appear on the stack in javascript debuggers.

JSObjectOps.defaultValue
on success, *vp must be a primitive value: per es5 §8.12.8, every object "must ensure that its [[defaultvalue]] internal method can return only primitive values." debug builds of spidermonkey will assert if a convert callback is successful but leaves *vp holding a primitive value.

JSObjectPrincipalsFinder
the two debugger functions js_stackframeprincipals and js_evalframeprincipals also use this callback.

JS_BeginRequest
in a debug build, this is enforced with assertions.

JS_DumpHeap
this article covers features introduced in spidermonkey 1.8 debug only.

JS_FlattenString
if a jsstring is known to be flat, you can use js_assert_string_is_flat to make a debug-checked cast.

JS_NewContext
in a debug build, large chunk sizes can degrade performance dramatically.

JS_NewObjectForConstructor
if the constructor argument is not an object jsval, this function will assert (in debug builds).

JS_SetContextCallback
in a debug build, if the callback returns false, the js engine will halt with an assertion.

JS_SetFunctionCallback
note that debuggers should probably use js_setcallhook in preference to this function, because it is invoked when the javascript stack is guaranteed to be in a consistent state (and therefore it is valid to inspect and modify local variables, generate stack traces, and set breakpoints.) callback syntax typedef void (* jsfunctioncallback)(const jsfunction *fun,const jsscript *scr, const j...

JS_THREADSAFE
in a debug build, this is enforced with assertions.

JS_TracerInit
in the latter case, the only operations the callback may perform on thing are to call js_tracechildren or the debug-only js_printtracethinginfo function.

SpiderMonkey 1.8.5
the team is considering the removal of tinyids js_threadsafe is going away, with future versions supporting only thread-safe builds a new debugging api is on the way to replace jsd.

SpiderMonkey 1.8.7
the team is considering the removal of tinyids js_threadsafe is going away, with future versions supporting only thread-safe builds a new debugging api is on the way to replace jsd.

SpiderMonkey 1.8.8
the team is considering the removal of tinyids js_threadsafe is going away, with future versions supporting only thread-safe builds a new debugging api is on the way to replace jsd.

SpiderMonkey 17
the team is considering the removal of tinyids js_threadsafe is going away, with future versions supporting only thread-safe builds a new debugging api is on the way to replace jsd.

SpiderMonkey 24
the team is considering the removal of tinyids js_threadsafe is going away, with future versions supporting only thread-safe builds a new debugging api is on the way to replace jsd.

SpiderMonkey 31
js_threadsafe is going away, with future versions supporting only thread-safe builds a new debugging api is on the way to replace jsd.

SpiderMonkey 38
js_threadsafe is going away, with future versions supporting only thread-safe builds a new debugging api is on the way to replace jsd.

Running Automated JavaScript Tests
u are not changing language-level functionality, you may wish to use jstests.py path_to_js_shell --exclude=test262 other options allow you to show the test command lines being run, command output and return codes, run tests named in a given file, exclude tests named in a given file, hide the progress bar, change the timeout, run skipped tests, print output in tinderbox format, run a test in the debugger, or run tests in valgrind.

SavedFrame
savedframe stacks should generally be captured, allocated, and live within the compartment that is being observed or debugged.

SpiderMonkey: The Mozilla JavaScript runtime
js debugger api reference api reference for the debugger object introduced in spidermonkey 1.8.6, which corresponds to gecko 8.0 (firefox 8.0 / thunderbird 8.0 / seamonkey 2.5).

Using RAII classes in Mozilla
(this is needed because the macro adds a parameter only when debug is defined, and in this case, it can't add the leading comma.) class moz_raii nsautoscriptblocker { public: explicit nsautoscriptblocker(moz_guard_object_notifier_only_param) { moz_guard_object_notifier_init; nscontentutils::addscriptblocker(); } ~nsautoscriptblocker() { nscontentutils::removescriptblocker(); } private: moz_decl_use_guard_object_notifier }; second, if the...

Secure Development Guidelines
v[]) { if (argc > 1) printf(argv[1]); } format string bugs: prevention easy to fix: always use a format string specifier: int main(int argc, char *argv[]) { if (argc > 1) printf("%s", argv[1]); } double free example: void* ptr = malloc(1024); if (error) { free(ptr); } free(ptr); double free: prevention set a pointer to null when it’s freed valgrind or malloc debugging can help detect those bugs use after free accessing data after a free() or delete can lead to undefined behavior some debug tools might be able catch some cases un-initialized data example: int main() { char *uninitialized_ptr; printf("0x%08x\r\n", uninitialized_ptr); return 0; } $ ./test 0x8fe0103 un-initialized data: prevention initialize your variables!

Signing Mozilla apps for Mac OS X
while testing and debugging for test and debug purposes, the easiest way to get a signing certificate is to use apple's keychain feature to create one.

XPCOM glue
at runtime (not compile time) (in debug builds) or your module just won't load (in optimized builds).

Avoiding leaks in JavaScript XPCOM components
further reading finding leaks in mozilla - how to debug leaks when they do occur.

Using XPCOM Utilities to Make Things Easier
in a debugging environment, this string will be printed to the screen when the component library is loaded or unloaded.

How To Pass an XPCOM Object to a New Window
getservice(components.interfaces.nsiwindowwatcher); var win = ww.openwindow(null, "chrome://myextension/content/debug.xul", "debug history", "chrome,centerscreen,resizable", myobject); note in this example that myobject is passed to the openwindow() method; you can pass any xpcom object (or any other value, for that matter) in this way.

Components.utils.Sandbox
debug() for more information on the built-in sandbox functions, please consult the source code.

Components.utils.setGCZeal
this method has no effect unless running in a debug build.

XPCShell Reference
see the documentation on debugdump() for the nsixpconnect interface for more information.

XPCshell Test Manifest Expressions
'android' os_version - the version of the operating system on which the test is being run toolkit - the graphics toolkit used by this build one of: 'windows', 'cocoa', 'gtk2', 'android' processor - the cpu which the code is compiled for one of: 'x86', 'x86_64', 'arm' bits - the pointer size of the cpu architecture, in bits one of 32, 64, possibly unknown debug - set to true if this build is a debug build, false otherwise crashreporter - set to true if this build has crash reporting code enabled, false otherwise.

xpcshell
(however, it might not be there if you have a non-debug version of firefox, mozilla, thunderbird, etc.) $ cd /opt/mozilla $ ./run-mozilla.sh ./xpcshell js> execute xpcshell from window the built xpcshell.exe can't be executed under the mozilla build shell(bash).

nsICommandLineHandler
example: category entry value command-line-handler b-jsdebug @mozilla.org/venkman/clh;1 command-line-handler c-extensions @mozilla.org/extension-manager/clh;1 command-line-handler m-edit @mozilla.org/composer/clh;1 command-line-handler m-irc @mozilla.org/chatzilla/clh;1 command-line-handler y-final @mozilla.org/browser/clh-final;1 ...

nsIContentSecurityPolicy
policy astring a read-only string version of the policy for debugging.

nsIEditor
void removeeditorobserver(in nsieditorobserver observer obsolete since gecko 18); void addeditactionlistener(in nsieditactionlistener listener); void removeeditactionlistener(in nsieditactionlistener listener); void adddocumentstatelistener(in nsidocumentstatelistener listener); void removedocumentstatelistener(in nsidocumentstatelistener listener); debug methods void dumpcontenttree(); void debugdumpcontent() ; void debugunittests(out long outnumtests, out long outnumtestsfailed); [notxpcom] boolean ismodifiablenode(in nsidomnode anode); constants load flags constant value description enone 0 enext 1 eprevious 2 enextword ...

nsIEventListenerService
content/events/public/nsieventlistenerservice.idlscriptable a service that can be used to get a list of listeners observing events; this is primarily useful for debuggers.

nsIHttpActivityDistributor
this is primarily useful for debuggers and other traffic monitoring tasks.

nsIJetpack
individual lines of the form //@line 1 "foo.js" can be used to specify filename and line number information for debugging purposes.

nsIMsgIdentity
useful for debugging.

nsITransferable
failure to do so will result in fatal assertions in debug builds.

NS_ENSURE_ARG_POINTER
refer to xpcom/glue/nsdebug.h for details.

NS_ERROR
summary macro throws a assertion (ns_assertion) with the text "error: (error text)", so writes this text to console (stderr) and to debug logs (nspr logging).

NS_WARNING
summary macro shows a warning on the console (stderr) and in debug logs (nspr logging).

XPCOM Interface Reference by grouping
nsiobserverservice nsiproperties nsiproperty nsipropertybag nsipropertybag2 nsipropertyelement nsiserversocket nsiserversocketlistener nsiservicemanager nsisocketprovider nsisocketproviderservice nsisockettransport nsisockettransportservice nsisupports nsiuuidgenerator debug nsistackframe device display nsiscreen nsiscreenmanager geolocation nsigeolocationprovider nsigeolocationupdate orientation nsiacceleration nsiaccelerationlistener nsiaccelerometer ...

XPCOM reference
rss feeds are implemented by nslocalmailfolder.ns ensure successmacrons ensure truemacrons_abort_if_falsethis was removed in bug 1127201ns_addrefmacrons_assertionmacrons_ensure_arg_pointermacrons_errorthrows a assertion (ns_assertion) with the text "error: (error text)", so writes this text to console (stderr) and to debug logs (nspr logging).

nsCOMPtr versus RefPtr
(although, confusingly, debug builds don't work this way).

Testing Mozilla code
the first part will focus on the modern and robust way of static-analysis and the second part will present the build-time static-analysis.debugging mozilla with valgrindthis page describes how to use valgrind (specifically, its memcheck tool) to find memory errors.firefox and address sanitizeraddress sanitizer (asan) is a fast memory error detector that detects use-after-free and out-of-bound bugs in c/c++ programs.

Account Provisioner
debugging the account provisioner dialog logs most if not all of its activities, which is useful for debugging.

Building a Thunderbird extension 1: introduction
there are also a number of extension and applications that are useful for testing and debugging thunderbird extensions, such as javascript consoles and xpcom inspectors.

Finding the code for a feature
(for debug builds, you can make it appear by default using "ac_add_options --enable-extensions=default,venkman,inspector" which is part of my standard configuration).

Thunderbird extensions
learn more about gloda: an overview of gloda how to create your first message query and read the gloda examples gloda internals: gloda debugging, gloda indexing more thunderbird-specific links some links may be out of date, but they still provide valuable information on the codebase.

Using MAPI with Thunderbird's Windows 7 developer builds
if you want to set a debug build as the default mail client, you need configure it manually: in the objdir/mozilla/dist/bin directory, copy mozmapi32.dll to mozmapi32_inuse.dll and mapiproxy to mapiproxy_inuse.dll.

Thunderbird
there's also information about how the review process works and how to use the mozilla symbol server to help with debugging.

CData
tchpad mdnfirefox" at js array position 36 (so 37 if count from 1), we see 183, and at 77 we see char code of 0 if casted to unsigned_char, if casted to char we see -73 at pos 36 but pos 77 still 0, if casted to jschar we see chineese characters in all spots expect spaces even null terminator is a chineese character console.info('ptrasarr.length:', ptrasarr.length); //console.log('debug-msg :: datacasted:', datacasted, uneval(datacasted), datacasted.tostring()); var charcode = []; var fromcharcode = [] for (var i=0; i<ptrasarr.length; i++) { //if known_len is correct, then will not hit null terminator so like in example of "_scratchpad/entehandle.js at master · noitidart/_scratchpad mdnfirefox" if you pass length of 77, then null term will not get hit by...

Plug-in Development Overview - Plugins
test your plug-in and debug as necessary.

Accessibility Inspector - Firefox Developer Tools
the accessibility inspector also uses this information to provide valuable accessibility debugging capabilities in the devtools.

Introduction to DOM Inspector - Firefox Developer Tools
used in concert with mozilla tools like venkman, the javascript debugger, the dom inspector can give you a complete view of any web page or dom-based application interface.

Breaking on exceptions - Firefox Developer Tools
to instruct the debugger to pause on an exception, tick these checkboxes in the breakpoints list: pause on exceptions pause on caught exceptions when an exception occurs, the line where it occurs is highlighted in the source pane, with a squiggly red line under the problematic code.

Highlight and inspect DOM nodes - Firefox Developer Tools
when you are working with dom notes in the debugger, you can easily highlight the node on the page or view it in the page inspector.

Pretty-print a minified file - Firefox Developer Tools
the debugger formats the source and displays it as a new file with a name like: "{ } [original-name]".

Search - Firefox Developer Tools
the debugger will display the number of matches in the code and highlight each result: using the outline tab if you are searching for a specific function within the current javascript file, you can use the outline tab in the debugger to find it quickly.

Set an XHR breakpoint - Firefox Developer Tools
to turn on the feature: open the debugger click on "pause on any url" which acts as a wild card, causing the code to pause on any call, or, click the plus sign next to the xhr breakpoints header, enter the url in which you are interested, and press enter.

Aggregate view - Firefox Developer Tools
the file name and line number is a link: if we click it, we go directly to that line in the debugger: inverted call stack the call stack view is top-down: it shows allocations that happen at that point or points deeper in the call tree.

Network monitor recording - Firefox Developer Tools
this is useful in situations where, for example, you are trying to get a stable view of a page for debugging purposes, but under normal circumstances the view keeps evolving due to persistent network requests.

Network request list - Firefox Developer Tools
open in new tab resends the request in a new tab — very useful for debugging asynchronous requests.

Network Monitor - Firefox Developer Tools
this means you can start debugging a page in, for example, the web console, then switch to the network monitor to see network activity without having to reload the page.

CSS Flexbox Inspector: Examine Flexbox layouts - Firefox Developer Tools
the flexbox inspector allows you to examine css flexbox layouts using the firefox devtools, which is useful for discovering flex containers on a page, examining and modifying them, debugging layout issues, and more.

Examine Event Listeners - Firefox Developer Tools
ows the word "event" next to elements in the html pane, that have event listeners bound to them: click the icon, then you'll see a popup listing all the event listeners bound to this element: each line contains: a right-pointing arrowhead; click to expand the row and show the listener function source code a curved arrow pointing to a stack; click it to show the code for the handler in the debugger the name of the event for which a handler was attached to this element the name and line number for the listener; you can also click here to expand the row and view the listener function source code a label indicating whether the event bubbles a label indicating the system that defines the event.

CSS Grid Inspector: Examine grid layouts - Firefox Developer Tools
the grid inspector allows you to examine css grid layouts using the firefox devtools, discovering grids present on a page, examining and modifying them, debugging layout issues, and more.

Page Inspector - Firefox Developer Tools
see remote debugging to learn how to connect the developer tools to a remote target.

Extension Storage - Firefox Developer Tools
this storage type is only shown when debugging extensions.

Style Editor - Firefox Developer Tools
the media sidebar works especially well with responsive design view for creating and debugging responsive layouts: from firefox 46 onwards, if an @media rule contains a screen size in a condition, then it is made clickable: clicking it then resizes the screen to that size using the responsive design view: creating and importing style sheets you can create a new style sheet by clicking the new button in the toolbar.

Split console - Firefox Developer Tools
as usual, $0 works as a shorthand for the element currently selected in the inspector: when you use the split console with the debugger, the console's scope is the currently executing stack frame.

Working with iframes - Firefox Developer Tools
if you select an entry in the list, all the tools in the toolbox - the inspector, the console, the debugger and so on - will now target only that iframe, and will essentially behave as if the rest of the page does not exist.

DedicatedWorkerGlobalScope - Web APIs
this is mainly useful for debugging purposes.

Document.requestStorageAccess() - Web APIs
debugging the storage access grant threshold may make it more difficult to test your website under the condition where firefox prompts the user for access.

Event.currentTarget - Web APIs
instead, you can either directly console.log(event.currenttarget) to be able to view it in the console or use the debugger statement, which will pause the execution of your code thus showing you the value of event.currenttarget.

FileException - Web APIs
the added complexity of using webworkers with this api makes debugging even more challenging.

GeolocationPositionError - Web APIs
specifications note that this is primarily intended for debugging use and not to be shown directly in a user interface.

In depth: Microtasks and the JavaScript runtime environment - Web APIs
when debugging or, possibly, when trying to decide upon the best approach to solving a problem around timing and scheduling of tasks and microtasks, there are things about how the javascript runtime operates under the hood that may be useful to understand.

IntersectionObserver.thresholds - Web APIs
debugging chaos may ensue.

LayoutShiftAttribution - Web APIs
the layoutshiftattribution interface of the layout instability api provides debugging information about elements which have shifted.

MediaRecorderErrorEvent() - Web APIs
some user agents add to the error object other properties that provide information such as stack dumps, the name of the javascript file and the line number where the error occurred, and other debugging aids, but you should not rely on this information in a production environment.

MediaTrackSupportedConstraints - Web APIs
instead, the specified constraints will be applied, with any unrecognized constraints stripped from the request.that can lead to confusing and hard to debug errors, so be sure to use getsupportedconstraints() to retrieve this information before attempting to establish constraints if you need to know the difference between silently ignoring a constraint and a constraint being accepted.

PerformanceObserver.observe() - Web APIs
unrecognized types are ignored, though the browser may output a warning message to the console to help developers debug their code.

PushManager.getSubscription() - Web APIs
turn; } // keep your server in sync with the latest subscriptionid sendsubscriptiontoserver(subscription); showcurlcommand(subscription); // set your ui to show they have subscribed for // push messages pushbutton.textcontent = 'disable push messages'; ispushenabled = true; }) .catch(function(err) { window.demo.debug.log('error during getsubscription()', err); }); }); specifications specification status comment push apithe definition of 'getsubscription()' in that specification.

PushManager.register() - Web APIs
example var req = navigator.push.register(); req.onsuccess = function(e) { var endpoint = req.result; debug("new endpoint: " + endpoint ); } req.onerror = function(e) { debug("error getting a new endpoint: " + json.stringify(e)); } specification specification status comment push api working draft defines the pushmanager interface.

PushManager.unregister() - Web APIs
example var req = navigator.push.unregister(pushendpoint); req.onsuccess = function(e) { var endpoint = req.result; debug("unregistered endpoint: " + endpoint ); } req.onerror = function(e) { debug("error unregistering the endpoint: " + json.stringify(e)); } specification specification status comment push api working draft defines the pushmanager interface.

RTCDataChannel.id - Web APIs
this can be also useful for logging and debugging purposes.

RTCIceCandidate.relatedAddress - Web APIs
example in this example, the candidate's type is checked, and then debugging output is presented, based on the candidate type, including the candidate's ip and relatedaddress.

RTCPeerConnection.signalingState - Web APIs
this value may also be useful during debugging, for example.

Request - Web APIs
you could then fetch this api request by passing the request object in as a parameter to a windoworworkerglobalscope.fetch() call, for example and get the response: fetch(request) .then(response => { if (response.status === 200) { return response.json(); } else { throw new error('something went wrong on api server!'); } }) .then(response => { console.debug(response); // ...

SharedWorkerGlobalScope - Web APIs
this is mainly useful for debugging purposes.

Multi-touch interaction - Web APIs
ngth) { case 1: // single tap` ev.target.style.background = "yellow"; break; case 2: // two simultaneous touches ev.target.style.background = "pink"; break; default: // more than two simultaneous touches ev.target.style.background = "lightblue"; } } event logging the functions are used to log event activity to the application window, to support debugging and learning about the event flow.

WebGLRenderingContext.getActiveAttrib() - Web APIs
it is generally used when querying unknown attributes either for debugging or generic library creation.

WebGLRenderingContext.getActiveUniform() - Web APIs
it is generally used when querying unknown uniforms either for debugging or generic library creation.

WebGLRenderingContext.getExtension() - Web APIs
ives oes_texture_float oes_texture_float_linear oes_texture_half_float oes_texture_half_float_linear oes_vertex_array_object ovr_multiview2 webgl_color_buffer_float webgl_compressed_texture_astc webgl_compressed_texture_atc webgl_compressed_texture_etc webgl_compressed_texture_etc1 webgl_compressed_texture_pvrtc webgl_compressed_texture_s3tc webgl_compressed_texture_s3tc_srgb webgl_debug_renderer_info webgl_debug_shaders webgl_depth_texture webgl_draw_buffers webgl_lose_context specifications specification status comment webgl 1.0the definition of 'webglrenderingcontext.getextension' in that specification.

WebGLRenderingContext.getShaderInfoLog() - Web APIs
it contains warnings, debugging and compile information.

WebGLRenderingContext.getSupportedExtensions() - Web APIs
ives oes_texture_float oes_texture_float_linear oes_texture_half_float oes_texture_half_float_linear oes_vertex_array_object ovr_multiview2 webgl_color_buffer_float webgl_compressed_texture_astc webgl_compressed_texture_atc webgl_compressed_texture_etc webgl_compressed_texture_etc1 webgl_compressed_texture_pvrtc webgl_compressed_texture_s3tc webgl_compressed_texture_s3tc_srgb webgl_debug_renderer_info webgl_debug_shaders webgl_depth_texture webgl_draw_buffers webgl_lose_context specifications specification status comment webgl 1.0the definition of 'webglrenderingcontext.getsupportedextensions' in that specification.

WebGLRenderingContext.vertexAttribPointer() - Web APIs
however, these functions are great for debugging a webgl context without touching the application code.

Using WebGL extensions - Web APIs
ives oes_texture_float oes_texture_float_linear oes_texture_half_float oes_texture_half_float_linear oes_vertex_array_object ovr_multiview2 webgl_color_buffer_float webgl_compressed_texture_astc webgl_compressed_texture_atc webgl_compressed_texture_etc webgl_compressed_texture_etc1 webgl_compressed_texture_pvrtc webgl_compressed_texture_s3tc webgl_compressed_texture_s3tc_srgb webgl_debug_renderer_info webgl_debug_shaders webgl_depth_texture webgl_draw_buffers webgl_lose_context enabling an extension before an extension can be used it has to be enabled using webglrenderingcontext.getextension().

WebGL: 2D and 3D graphics for the web - Web APIs
ives oes_texture_float oes_texture_float_linear oes_texture_half_float oes_texture_half_float_linear oes_vertex_array_object ovr_multiview2 webgl_color_buffer_float webgl_compressed_texture_astc webgl_compressed_texture_atc webgl_compressed_texture_etc webgl_compressed_texture_etc1 webgl_compressed_texture_pvrtc webgl_compressed_texture_s3tc webgl_compressed_texture_s3tc_srgb webgl_debug_renderer_info webgl_debug_shaders webgl_depth_texture webgl_draw_buffers webgl_lose_context events webglcontextlost webglcontextrestored webglcontextcreationerror constants and types webgl constants webgl types webgl 2 webgl 2 is a major update to webgl which is provided through the webgl2renderingcontext interface.

Signaling and video calling - Web APIs
our example doesn't use this for anything, but it can be useful to watch these events for debugging purposes, as well as to detect when candidate collection has finished.

WebSocket.onmessage - Web APIs
syntax awebsocket.onmessage = function(event) { console.debug("websocket message received:", event); }; value an eventlistener.

Tools for analyzing Web Audio usage - Web APIs
while working on your web audio api code, you may find that you need tools to analyze the graph of nodes you create or to otherwise debug your work.

Web Audio API - Web APIs
tools for analyzing web audio usagewhile working on your web audio api code, you may find that you need tools to analyze the graph of nodes you create or to otherwise debug your work.

Web Locks API - Web APIs
this can be useful when debugging, for example, identifying why a lock could not be acquired.

Functions and classes available to Web Workers - Web APIs
41 (41) (yes) (yes) (yes) console api provides access to the browser's debugging console (e.g., the web console in firefox).

Window.console - Web APIs
these methods are intended for debugging purposes only and should not be relied on for presenting information to end users.

Window: rejectionhandled event - Web APIs
this can be used in debugging and for general application resiliency, in tandem with the unhandledrejection event, which is sent when a promise is rejected but there is no hander for the rejection.

Window: unhandledrejection event - Web APIs
this is useful for debugging and for providing fallback error handling for unexpected situations.

Window - Web APIs
window.console read only returns a reference to the console object which provides access to the browser's debugging console.

Worker() - Web APIs
name: a domstring specifying an identifying name for the dedicatedworkerglobalscope representing the scope of the worker, which is mainly useful for debugging purposes.

WorkerGlobalScope.console - Web APIs
example this property allows you to have access to a browser console for debugging purposes, inside a worker.

msWriteProfilerMark - Web APIs
notes mswriteprofilermark enables you to inject dom based performance markers in addition to existing javascript api to learn exactly when parts of the page are being rendered, building a waterfall view for every one of our impressions showing latency per object, which can be useful for more accurately debugging real users perf issues.

Web APIs
handler userproximityevent v vttcue vttregion validitystate videoconfiguration videoplaybackquality videotrack videotracklist visualviewport w webgl_color_buffer_float webgl_compressed_texture_astc webgl_compressed_texture_atc webgl_compressed_texture_etc webgl_compressed_texture_etc1 webgl_compressed_texture_pvrtc webgl_compressed_texture_s3tc webgl_compressed_texture_s3tc_srgb webgl_debug_renderer_info webgl_debug_shaders webgl_depth_texture webgl_draw_buffers webgl_lose_context wakelock wakelocksentinel waveshapernode webgl2renderingcontext webglactiveinfo webglbuffer webglcontextevent webglframebuffer webglprogram webglquery webglrenderbuffer webglrenderingcontext webglsampler webglshader webglshaderprecisionformat webglsync webgltexture webgltransformfeedback webglunifo...

ARIA Test Cases - Accessibility
reference to link example note regarding dojo/dijit test files the main purpose of dojo's dijit test files are for dojo developers to exercise and debug the code.

Web applications and ARIA FAQ - Accessibility
several inspecting and debugging tools exist to help you test aria in action: object inspector on windows accessibility inspector on os x accprobe on linux firebug's dom inspector the accessibility inspector for firebug the audits tab in chrome devtools there are several free or open source screen readers that can be used to do hands-on testing with aria.

Implementing a Microsoft Active Accessibility (MSAA) Server - Accessibility
at vendors have typically spent the most time making windows with these classes work, so they are fully debugged.

Robust - Accessibility
see debugging html for a practical guide.

Using CSS transitions - CSS: Cascading Style Sheets
this is the best way to configure transitions, as it makes it easier to avoid out of sync parameters, which can be very frustrating to have to spend lots of time debugging in css.

Specificity - CSS: Cascading Style Sheets
using !important, however, is bad practice and should be avoided because it makes debugging more difficult by breaking the natural cascading in your stylesheets.

Guide to scroll anchoring - CSS: Cascading Style Sheets
what if i need to debug it?

Getting Started - Developer guides
note 2: if you do not set header cache-control: no-cache the browser will cache the response and never re-submit the request, making debugging challenging.

<button>: The Button element - HTML: Hypertext Markup Language
text/plain: specified as a debugging aid; shouldn’t be used for real form submission.

<figure>: The Figure with Optional Caption element - HTML: Hypertext Markup Language
"; "; txt+= "browser version: " + navigator.appversion + "; "; txt+= "cookies enabled: " + navigator.cookieenabled + "; "; txt+= "platform: " + navigator.platform + "; "; txt+= "user-agent header: " + navigator.useragent + "; "; console.log("navigatorexample", txt); } </pre> </figure> quotations <figure> <figcaption><cite>edsger dijkstra:</cite></figcaption> <blockquote>if debugging is the process of removing software bugs, then programming must be the process of putting them in.</blockquote> </figure> poems <figure> <p style="white-space:pre"> bid me discourse, i will enchant thine ear, or like a fairy trip upon the green, or, like a nymph, with long dishevell'd hair, dance on the sands, and yet no footing seen: love is a spirit all compact of fire, not g...

<form> - HTML: Hypertext Markup Language
text/plain: introduced by html5 for debugging purposes.

<input type="image"> - HTML: Hypertext Markup Language
text/plain plain text; mostly useful only for debugging, so you can easily see the data that's to be submitted.

<input type="submit"> - HTML: Hypertext Markup Language
text/plain plain text; mostly useful only for debugging, so you can easily see the data that's to be submitted.

CORS errors - HTTP
however, if the endpoint is meant to be available, some debugging is needed to succeed.

HTTP conditional requests - HTTP
this is a race condition and leads to problematic behaviors, which are difficult to detect and to debug: there is no way to deal with this problem without annoying one of the two clients.

Forwarded - HTTP
this header is used for debugging, statistics, and generating location-dependent content and by design it exposes privacy sensitive information, such as the ip address of the client.

Index - HTTP
102 sourcemap http, http header, reference, response header, header the sourcemap http response header links generated code to a source map, enabling the browser to reconstruct the original source and present the reconstructed original in the debugger.

SourceMap - HTTP
the sourcemap http response header links generated code to a source map, enabling the browser to reconstruct the original source and present the reconstructed original in the debugger.

X-Forwarded-For - HTTP
this header is used for debugging, statistics, and generating location-dependent content and by design it exposes privacy sensitive information, such as the ip address of the client.

X-Forwarded-Host - HTTP
this header is used for debugging, statistics, and generating location-dependent content and by design it exposes privacy sensitive information, such as the ip address of the client.

TRACE - HTTP
the http trace method performs a message loop-back test along the path to the target resource, providing a useful debugging mechanism.

Proxy servers and tunneling - HTTP
the ip address of the original client is often used for debugging, statistics, or generating location-dependent content.

HTTP
tools & resources helpful tools and resources for understanding and debugging http.

JavaScript data types and data structures - JavaScript
strings are easy to debug (what you see printed is always what is in the string).

Control flow and error handling - JavaScript
try { throw 'myexception'; // generates an exception } catch (err) { // statements to handle any exceptions logmyerrors(err); // pass exception object to error handler } best practice: when logging errors to the console inside a catch block, using console.error() rather than console.log() is advised for debugging.

Functions - JavaScript
providing a name allows the function to refer to itself, and also makes it easier to identify the function in a debugger's stack traces: const factorial = function fac(n) { return n < 2 ?

JavaScript modules - JavaScript
you'll still get syntax errors shown in the devtools, but you'll not be able to use some of the debugging techniques you might have expected to use.

Regular expressions - JavaScript
regex tester an online regex builder/debugger regex visualizer an online visual regex tester.

Using Promises - JavaScript
these make it possible to offer fallback error handling for promises, as well as to help debug issues with your promise management.

Warning: -file- is being assigned a //# sourceMappingURL, but already has one - JavaScript
with source maps, the debugger can map the code being executed to the original source files.

SyntaxError: Using //@ to indicate sourceURL pragmas is deprecated. Use //# instead - JavaScript
with source maps, the debugger can map the code being executed to the original source files.

SyntaxError: test for equality (==) mistyped as assignment (=)? - JavaScript
to help debugging, javascript (with strict warnings enabled) warns about this pattern.

SyntaxError: missing variable name - JavaScript
sorry :( var debugger = "whoop"; // syntaxerror: missing variable name declaring multiple variables pay special attention to commas when declaring multiple variables.

JavaScript error reference - JavaScript
these errors can be a helpful debugging aid, but the reported problem isn't always immediately clear.

Array.prototype.toSource() - JavaScript
you can call tosource while debugging to examine the contents of an array.

Error.prototype.stack - JavaScript
see also debug eval sources in the debugger docs and this blog post.

Error.prototype.fileName - JavaScript
if called from a debugger context, the firefox developer tools for example, "debugger eval code" is returned.

Error - JavaScript
stomerror extends error { constructor(foo = 'bar', ...params) { // pass remaining arguments (including vendor specific ones) to parent constructor super(...params) // maintains proper stack trace for where our error was thrown (only available on v8) if (error.capturestacktrace) { error.capturestacktrace(this, customerror) } this.name = 'customerror' // custom debugging information this.foo = foo this.date = new date() } } try { throw new customerror('baz', 'bazmessage') } catch(e) { console.error(e.name) //customerror console.error(e.foo) //baz console.error(e.message) //bazmessage console.error(e.stack) //stacktrace } es5 custom error object all browsers include the customerror constructor in the stack trace when using a pr...

Function.prototype.toSource() - JavaScript
you can call tosource() while debugging to examine the contents of an object.

Generator.prototype.throw() - JavaScript
for debugging purposes, it is useful to make it an instanceof error.

Object.prototype.toSource() - JavaScript
you can call tosource() while debugging to examine the contents of an object.

Promise.reject() - JavaScript
for debugging purposes and selective error catching, it is useful to make reason an instanceof error.

Symbol() constructor - JavaScript
a description of the symbol which can be used for debugging but not to access the symbol itself.

Symbol.prototype.description - JavaScript
description symbol objects can be created with an optional description which can be used for debugging but not to access the symbol itself.

SyntaxError() constructor - JavaScript
', 'somefile.js', 10); } catch (e) { console.error(e instanceof syntaxerror); // true console.error(e.message); // hello console.error(e.name); // syntaxerror console.error(e.filename); // somefile.js console.error(e.linenumber); // 10 console.error(e.columnnumber); // 0 console.error(e.stack); // @debugger eval code:3:9 } specifications specification ecmascript (ecma-262)the definition of 'nativeerror constructor' in that specification.

SyntaxError - JavaScript
', 'somefile.js', 10); } catch (e) { console.error(e instanceof syntaxerror); // true console.error(e.message); // hello console.error(e.name); // syntaxerror console.error(e.filename); // somefile.js console.error(e.linenumber); // 10 console.error(e.columnnumber); // 0 console.error(e.stack); // @debugger eval code:3:9 } specifications specification ecmascript (ecma-262)the definition of 'syntaxerror' in that specification.

WebAssembly.Module.customSections() - JavaScript
the wast2wasm command available as part of the wabt tool has a --debug-names option — specify this during conversion to get a .wasm with a names custom section, for example: wast2wasm simple-name-section.was -o simple-name-section.wasm --debug-names examples using customsections the following example (see the custom-section.html source and live example) compiles the loaded simple-name-section.wasm byte code.

undefined - JavaScript
while it is possible to use it as an identifier (variable name) in any scope other than the global scope (because undefined is not a reserved word), doing so is a very bad idea that will make your code difficult to maintain and debug.

for...in - JavaScript
it may be most practically used for debugging purposes, being an easy way to check the properties of an object (by outputting to the console or otherwise).

with - JavaScript
if it were not, one can see how this would be a difficult issue to debug.

JavaScript reference - JavaScript
y.runtimeerror statements javascript statements and declarations control flowblock break continue empty if...else switch throw try...catch declarations var let const functions and classes function function* async function return class iterations do...while for for each...in for...in for...of for await...of while other debugger import label with expressions and operators javascript expressions and operators.

JavaScript shells - JavaScript
they are extremely useful for developing and debugging code.