AddressErrors.region - Web APIs
an object based on addresserrors includes a region property when the address's region property couldn't be validated.
... syntax var regionerror = addresserrors.region; value if the value specified in the paymentaddress object's region property could not be validated, this property contains a domstring offering a human-readable explanation of the validation error and offers suggestions for correcting it.
... if the region value was validated successfully, this property is not included in the addresserrors object.
... specifications specification status comment payment request apithe definition of 'addresserrors.region' in that specification.

AddressErrors.regionCode - Web APIs
an object based on addresserrors includes a regioncode property when the address's regioncode property couldn't be validated.
... syntax var regioncodeerror = addresserrors.regioncode; value if the value specified in the paymentaddress object's regioncode property could not be validated, this property contains a domstring offering a human-readable explanation of the validation error and offers suggestions for correcting it.
... if the regioncode value was validated successfully, this property is not included in the addresserrors object.
... specifications specification status comment payment request apithe definition of 'addresserrors.regioncode' in that specification.

AddressErrors.sortingCode - Web APIs
an object based on addresserrors includes a sortingcode property when the address's sortingcode property couldn't be validated.
... syntax var sortingcodeerror = addresserrors.sortingcode; value if the value specified in the paymentaddress object's sortingcode property could not be validated, this property contains a domstring offering a human-readable explanation of the validation error and offers suggestions for correcting it.
... if the sortingcode value was validated successfully, this property is not included in the addresserrors object.
... specifications specification status comment payment request apithe definition of 'addresserrors.sortingcode' in that specification.

PayerErrors - Web APIs
the payererrors dictionary is used by the payment request api to indicate the presence of—and to explain how to correct—validation errors in the payer details.
... for each field in the payment information that fails validation, the payererrors object contains a string explaining the error.
...if this property is absent from the payererrors object, the email address passed validation.
... example specifications specification status comment payment request apithe definition of 'payererrors' in that specification.

AddressErrors.country - Web APIs
an object based on addresserrors includes a country property if during validation of the address the specified value of country was determined to be invalid.
... syntax var countryerror = addresserrors.country; value if an error occurred during validation of the address due to the country property having an invalid value, this property is set to a domstring providing a human-readable error message explaining the validation error.
... specifications specification status comment payment request apithe definition of 'addresserrors.country' in that specification.

Errors
this page lists the errors that can be raised due to firefox's anti-tracking functionality, governed by the storage access policy.

Index - Web APIs
29 addresserrors api, address, addresserrors, dictionary, errors, interface, payment address, payment request, payment request api, reference, payment, paymentaddress the addresserrors dictionary is used by the payment request api to to report validation errors in a physical address (typically a billing address or a shipping address).
... 30 addresserrors.addressline api, addresserrors, error, payment request, payment request api, property, reference, validation, addressline, payment an object based on addresserrors includes an addressline property when validation of the address finds one or more errors in the array of strings in the address's addressline.
... 31 addresserrors.city api, address, addresserrors, error, payment request, payment request api, property, read-only, reference, city, payment an object based on addresserrors includes a city property when validation of the address fails for the value given for the address's city property.
...And 40 more matches

What went wrong? Troubleshooting JavaScript - Learn web development
never fear — this article aims to save you from tearing your hair out over such problems by providing you with some tips on how to find and fix errors in javascript programs.
... types of error generally speaking, when you do something wrong in code, there are two main types of error that you'll come across: syntax errors: these are spelling errors in your code that actually cause the program not to run at all, or stop working part way through — you will usually be provided with some error messages too.
... logic errors: these are errors where the syntax is actually correct but the code is not what you intended it to be, meaning that program runs successfully but gives incorrect results.
...And 13 more matches

Debugging HTML - Learn web development
this article will introduce you to some tools that can help you find and fix errors in html.
...well, generally when you do something wrong in code, there are two main types of error that you'll come across: syntax errors: these are spelling errors in your code that actually cause the program not to run, like the rust error shown above.
... logic errors: these are errors where the syntax is actually correct, but the code is not what you intended it to be, meaning that the program runs incorrectly.
...And 11 more matches

Error codes returned by Mozilla APIs
the following tables list errors that can occur when calling various mozilla apis.
...for example, by using components.results.ns_error_not_initialized general errors the following errors are general and can occur when using any component.
... ns_error_failure (0x80004005) this is the most general of all the errors and occurs for all errors for which a more specific error code does not apply.
...And 10 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.
...logging template results there are two main ways in which template errors may be detected.
... template errors the second type of template error is a syntax error is the template rules, for example, a missing attribute or a tag out of place.
...And 8 more matches

Index
14 introduction to xpcom for the dom developing mozilla warning: this document has not yet been reviewed by the dom gurus, it might contain some errors.
... 27 components.results xpcom:language bindings, xpconnect components.results is a read-only object whose properties are the names listed as the first parameters of the macros in js/xpconnect/src/xpc.msg (also at table of errors), with the value of each corresponding to that constant's value.
... 139 nsresult errors, mozilla, reference, référence(2), xpcom, xpcom api reference the nsresult data type is a strongly-typed enum used to represent a value returned by an xpcom function; these are typically error or status codes.
...And 8 more matches

PaymentResponse.retry() - Web APIs
syntax retrypromise = paymentrequest.retry(errorfields); parameters errorfields a paymentvalidationerrors object, with the following properties: error optional a general description of a payment error from which the user may attempt to recover by retrying the payment, possibly after correcting mistakes in the payment information.
... error can be provided all by itself to provide only a generic error message, or in concert with the other properties to serve as an overview while other properties' values gude the user to errors in specific fields in the payment form.
... payer optional a payererrors compliant object which provides appropriate error messages for any of the fields describing the payer which failed validation.
...And 8 more matches

View Source - Firefox Developer Tools
syntax highlighting (toggle) applies syntax highlighting to the code.when syntax highlighting is on, view source also highlights parsing errors in red.
... hovering your mouse over errors displays a tooltip explaining the error.
... this feature is useful when you're looking for html errors.
...And 7 more matches

Using IndexedDB - Web APIs
your code might look something like this: var db; var request = indexeddb.open("mytestdatabase"); request.onerror = function(event) { console.log("why didn't you allow my web app to use indexeddb?!"); }; request.onsuccess = function(event) { db = event.target.result; }; handling errors as mentioned above, error events bubble.
...if you want to avoid adding error handlers to every request, you can instead add a single error handler on the database object, like so: db.onerror = function(event) { // generic error handler for all errors targeted at this database's // requests!
... console.error("database error: " + event.target.errorcode); }; one of the common possible errors when opening a database is ver_err.
...And 7 more matches

Eclipse CDT
the benefit of building from inside eclipse is that build errors will appear in the problems tab at the bottom of the window, and from there you can double click on the build error and it will take you straight to the source file and line where the problem occurred.
...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.
...this is responsible for most of the parse errors in the source files displayed in eclipse.
...And 6 more matches

WebGL best practices - Web APIs
general topics address and eliminate webgl errors your application should run without generating any webgl errors (as returned by geterror).
...after too many errors (32 in firefox), webgl stops generating descriptive messages, which really hinders debugging.
... the only errors a well-formed page generates are out_of_memory and context_lost.
...And 6 more matches

Handling common HTML and CSS problems - Learn web development
let's go forth and look at how we can reduce cross browser errors that result from html/css.
... basically, it is a matter of checking whether your html and css code is well formed and doesn't contain any syntax errors.
...one service that can do this is the w3c markup validation service, which allows you to point to your code, and returns a list of errors: css has a similar story — you need to check that your property names are spelled correctly, property values are spelled correctly and are valid for the properties they are used on, you are not missing any curly braces, and so on.
...And 5 more matches

Console messages - Firefox Developer Tools
js javascript errors contain a "learn more" link that takes you to the javascript error reference containing additional advice for fixing issues: source maps the web console understands source maps.
...then any messages or errors your source generates will show up in the web console with a link back to the original source, not the compressed version.
... reflow events are logged as "reflow" messages, as distinct from css errors or warnings.
...And 5 more matches

Web Console remoting - Firefox Developer Tools
these can be: page errors, window.console api messages, network activity, and file activity.
...when you attach to the global consoleactor you receive all of the network requests, page errors, and the other events from all of the tabs and windows, including chrome errors and network events.
...you can only get cached messages for page errors and console api calls.
...And 5 more matches

Sensor APIs - Web APIs
checking for thrown errors when instantiating a sensor object.
... listening for errors thrown during its use.
... handling the errors gracefully so that the user experience is enhanced rather than degraded.
...And 5 more matches

TypeScript support in Svelte - Learn web development
one of the big benefits is enabling ides to provide a richer environment for spotting common errors as you type the code.
...this package allows you to detect errors and warnings normally displayed by a code editor from the command line, which makes it pretty useful for running it in a continuous integration (ci) pipeline.
... just run npm run validate to check for unused css, and return a11y hints and typescript compile errors.
...And 4 more matches

Introduction to automated testing - Learn web development
to update npm, use the following command in your terminal: npm install npm@latest -g note: if the above command fails with permissions errors, fixing npm permissions should sort you out.
...a reasonable set of basic functionalities to run on our project is as follows: html-tidy, css-lint, and js-hint to lint and report/fix common html/css/js errors (see gulp-htmltidy, gulp-csslint, gulp-jshint).
...we first run htmltidy() on the source, which goes through and fixes errors in our file.
...And 4 more matches

Handling common JavaScript problems - Learn web development
linters as with html and css, you can ensure better quality, less error-prone javascript code using a linter, which points out errors and can also flag up warnings about bad practices, etc., and be customized to be stricter or more relaxed in their error/warning reporting.
... online the jshint homepage provides an online linter, which allows you to enter your javascript code on the left and provides an output on the right, including metrics, warnings, and errors.
... after the packages have finished installing, try loading up a javascript file: you'll see any issues highlighted with green (for warnings) and red (for errors) circles next to the line numbers, and a separate panel at the bottom provides line numbers, error messages, and sometimes suggested values or other fixes.
...And 4 more matches

Troubleshooting XPCOM components registration
there are several common reasons that registration can fail: a component that is a binary (shared library) fails to load a javascript component has parsing errors the shared library loaded correctly, but registration was not successful did registration succeed?
...chrome errors must be enabled.
...set nspr_log_modules=nsnativemoduleloader:5 set nspr_log_file=c:\path\to\logfile "c:\program files\mozilla firefox\firefox.exe" examining this log for warning and errors may provide valuable clues why the component failed to load.
...And 4 more matches

The Valgrind Test Job
the valgrind test job builds the browser and runs it under valgrind, which can detect various common memory-related errors.
... understanding errors for each problem that valgrind finds, it emits a message describing the problem, along with a stack trace indicating where the problem occurs.
... it also prints a suppression, which is a sequence of text that can be put in a suppression file (and specified via valgrind's --suppressions option) if you want valgrind to ignore such errors in future runs.
...And 4 more matches

Strict mode - JavaScript
strict mode makes several changes to normal javascript semantics: eliminates some javascript silent errors by changing them to throw errors.
...changes generally fall into these categories: changes converting mistakes into errors (as syntax errors or at runtime), changes simplifying how the particular variable for a given use of a name is computed, changes simplifying eval and arguments, changes making it easier to write "secure" javascript, and changes anticipating future ecmascript evolution.
... converting mistakes into errors strict mode changes some previously-accepted mistakes into errors.
...And 4 more matches

Index - Archive of obsolete content
432 error console extensions, extensions:tools, javascript, javascript:tools, tools, web development, web development:tools the error console is a tool available in most mozilla-based applications that is used for reporting errors in the application chrome and in web pages user opens.
... it reports javascript-related errors and warnings, css errors and arbitrary messages from chrome code.
... 1677 template logging debugging problems with a template can be difficult as many problems are logic errors that are often not possible to determine automatically.
...And 3 more matches

Accessibility Information for Web Authors - Accessibility
automated checking & repair cynthia says™ from hisoftware® company "cynthia says™" is a free online webpage accessibility validation service that is designed to identify errors in webpage related to section 508 standards and/or the wcag guidelines.
...the web author chooses the guidelines (as a basis for errors and warnings) to be used by "cynthia says™": section 508, wcag priorities 1, 2 and 3.
... wave 4.0 beta (web accessibility versatile evaluator) from webaim and sponsored by temple university institute on disabilities wave 4.0 beta is another powerful, free online webpage accessibility validation service that identifies accessibility errors and reports accessibility warnings about webpage related to section 508 standards and/or the wcag guidelines.
...And 3 more matches

JavaScript error reference - JavaScript
below, you'll find a list of errors which are thrown by javascript.
... these errors can be a helpful debugging aid, but the reported problem isn't always immediately clear.
... the pages below will provide additional details about these errors.
...And 3 more matches

Troubleshooting XForms Forms - Archive of obsolete content
introduction the idea of this page is to collect some solutions to some of the common errors typically made when creating an xforms form.
...it checks your form for a lot of errors.
... it is not perfect, but it can spot a lot of errors.
...And 2 more matches

Index - MDN Web Docs Glossary: Definitions of Web-related terms
2 404 glossary, http errors, infrastructure, navigation a 404 is a standard response code meaning that the server cannot find the requested resource.
... 3 502 502, bad gateway, glossary, http errors, infrastructure, navigation an http error code meaning "bad gateway".
...in javascript syntax errors are a very common source of exceptions.
...And 2 more matches

Introducing a complete toolchain - Learn web development
code linting tools linting helps with code quality but also is a way to catch potential errors earlier during development.
...here is an example eslint output: ./my-project/src/index.js 2:8 error 'react' is defined but never used no-unused-vars 22:20 error 'body' is defined but never used no-unused-vars 96:19 error 'b' is defined but never used no-unused-vars ✖ 3 problems (3 errors, 0 warnings) note: we'll install eslint in the next section; don't worry about this for now.
...it's not a prerequisite of developing for the web, but it's useful to have the tools configured correctly if they’re going to help catch errors during development — which eslint is particularly useful for.
...And 2 more matches

Links and Resources
online accessibility validators there are now a few available and excellent online accessibility validators which check single webpages according to checkpoints of wcag guidelines and then reports errors or warnings.
...the accessibility report will contain errors and warnings for "automatic checkpoints" and "manual checkpoints"; detailed and useful information (line numbers, instances/occurences, textual references to guidelines) will be included for web authors.
... cynthia says™ from hisoftware® company "cynthia says™" is a free online webpage accessibility validation service that identifies accessibility errors in webpage related to section 508 standards and/or the wcag guidelines.
...And 2 more matches

Examples
mport("resource://gre/modules/osfile.jsm") let path = os.path.join(os.constants.path.tmpdir, "file.txt"); let promise = os.file.exists(path); let newpromise = promise.then(function onfulfill(aexists) { if (aexists) { console.log("you have file.txt in your temporary directory."); } else { throw new error("you don't have file.txt in your temporary directory."); } }); // unexpected errors should always be reported at the end of a promise chain.
...ls.import("resource://gre/modules/osfile.jsm") let path = os.path.join(os.constants.path.tmpdir, "file.txt"); let promise = os.file.exists(path); let newpromise = promise.then(function onfulfill(aexists) { if (aexists) { console.log("you have file.txt in your temporary directory."); } else { console.log("you don't have file.txt in your temporary directory."); } }); // unexpected errors should always be reported at the end of a promise chain.
...let promise = promisevalueaftertimeout("value", 1000); let newpromise = promise.then(function onfulfill(avalue) { console.log("fulfilled with this value: " + avalue); }, function onreject(areason) { console.log("rejected with this reason: " + areason); }); // unexpected errors should always be reported at the end of a promise chain.
...And 2 more matches

PromiseWorker.jsm
this is seen in a simple demo github :: promiseworker custom errors demo - main thread setup.
...myworker.exceptionhandlers['customerror'] = customerror.frommsg; this is seen in a simple demo at github :: promiseworker custom errors demo - worker side setup.
... the complete demo is found here: github :: promiseworker custom errors demo catching the promise from the worker, it is not possible, as of firefox 40, to cause the promise on the main thread catch.
...And 2 more matches

JS::CompileOptions
methods of js::readonlycompileoptions method description bool mutederrors() const determines if errors are muted.
...this allows an attack by which a malicious website loads a sensitive file (say, a bank statement) cross-origin (using the user's cookies), and sniffs the generated syntax errors (via a window.onerror handler) for juicy morsels of its contents.
... to counter this attack, html5 specifies that script errors should be sanitized ("muted") when the script is not same-origin with the global for which it is loaded.
...And 2 more matches

nsIZipWriter
operations performed on the queue throw any errors that occur out to the observer.
...using backward slash will not throw any errors but if this was an xpi file, firefox would not be able to read it properly.
... other errors may be thrown if a failure to complete the zip file occurs.
...And 2 more matches

spellcheck - HTML: Hypertext Markup Language
the spellcheck global attribute is an enumerated attribute defines whether the element may be checked for spelling errors.
... it may have the following values: true, which indicates that the element should be, if possible, checked for spelling errors; false, which indicates that the element should not be checked for spelling errors.
...this default value may also be inherited, which means that the element content will be checked for spelling errors only if its nearest ancestor has a spellcheck state of true.
...And 2 more matches

Using Promises - JavaScript
promises solve a fundamental flaw with the callback pyramid of doom, by catching all errors, even thrown exceptions and programming errors.
...these handlers are global per context, so all errors will go to the same event handlers, regardless of source.
...specifically, a nested catch only catches failures in its scope and below, not errors higher up in the chain outside the nested scope.
...And 2 more matches

Transitioning to strict mode - JavaScript
differences from non-strict to strict syntax errors when adding 'use strict';, the following cases will throw a syntaxerror before the script is executing: octal syntax var n = 023; with statement using delete on a variable name delete myvariable; using eval or arguments as variable or function argument name using one of the newly reserved keywords (in prevision for ecmascript 2015): implements, interface, let, package, private, protected,...
... public, static, and yield declaring function in blocks if (a < b) { function f() {} } obvious errors declaring twice the same name for a property name in an object literal {a: 1, b: 3, a: 7} this is no longer the case in ecmascript 2015 (bug 1041128).
... declaring two function parameters with the same name function f(a, b, b) {} these errors are good, because they reveal plain errors or bad practices.
...And 2 more matches

core/promise - Archive of obsolete content
you can chain multiple then functions, because then returns a promise resolved to a return value of an operation and errors propagate through the promise chains.
...that code then needs its own try/catch block to handle errors there.
... then(null, function handleparseerror(error) { // handle here both `readasync` and `parse` errors.
... treat errors as promises now that we can create all kinds of eventual values, it's useful to have a way to create eventual errors.

Error Console - Archive of obsolete content
the error console is a tool available in most mozilla-based applications that is used for reporting errors in the application chrome and in web pages user opens.
... it reports javascript-related errors and warnings, css errors and arbitrary messages from chrome code.
...see setting up extension development environment#development preferences for the preferences you should set if you want to see errors from firefox and extensions in the error console.
... types of errors error usually a syntax error that prevents the program from compiling.

Using Visual Studio as your XUL IDE - Archive of obsolete content
5.1 localization using dtd you will get validation errors in visual studio, if you are localizing your xul files.
...as vs doesn't know how the chrome protocol works it can't detect where the dtd file is really located and thus will give you errors wherever you use the entities that are declared in this file.
...as preprocessor directives are not valid xml, visual studio will mark them as errors in your xul files.
... 5.3 javascript related you will get validation errors for javascript code whenever using the keywords "const" and "let".

Debugging a XULRunner Application - Archive of obsolete content
xulrunner.exe /path/to/application.ini -jsconsole by default the js console only shows errors from web content.
... to show errors in chrome javascript, the pref pref("javascript.options.showinconsole", true) must be set.
... to log js errors to disk, set the environment variable xre_console_log to the path to the filename.
... note the "new in firefox 3" attribute "contentaccessible" on https://developer.mozilla.org/en/chrome_registration so as per http://markmail.org/message/ezbomhkw3bgqjllv#query:x-jsd+page:1+mid:xvlr7odilbyhn6v7+state:results change the manifest to have this line: content venkman jar:venkman.jar!/content/venkman/ contentaccessible=yes i get errors about not being able to open contentareautils.js, contentareadd.js, findutils.js, or contentareautils.js...

LiveConnect Overview - Archive of obsolete content
netscape.javascript.jsexception allows java code to handle javascript errors.
...this allows your java code to handle errors in javascript code execution which appear in java as exceptions of type jsexception.
...note: a more realistic example would place the call to getmember inside a try...catch statement to handle errors of type jsexception.
...when you are evaluating javascript code in java, the following situations can cause run-time errors: the javascript code is not evaluated, either due to a javascript compilation error or to some other error that occurred at run time.

CSS and JavaScript accessibility best practices - Learn web development
the client-side validation is still really useful for reporting errors — users can know about mistakes they make instantly, rather than having to wait for a round trip to the server and a page reload.
...if there are errors (if(errorlist.innerhtml !== '')) then we stop the form submitting (using preventdefault()), and display any error messages that have been created (see below).
... this mechanism means that the errors will only be shown if there are errors, which is better for usability.
... as a final note, we have used some wai-aria attributes in our demo to help solve accessibility problems caused by areas of content constantly updating without a page reload (screen readers won't pick this up or alert users to it by default): <div class="errors" role="alert" aria-relevant="all"> <ul> </ul> </div> we will explain these attributes in our next article, which covers wai-aria in much more detail.

How do you make sure your website works properly? - Learn web development
frequent errors the most frequent errors that we find are these: typos in the address we wanted to type http://demozilla.examplehostingprovider.net/ but typed too fast and forgot an “l”: the address cannot be found.
... 404 errors many times the error just results just from a typo, but sometimes maybe you either forgot to upload a resource or you lost your network connection while you were uploading your resources.
... javascript errors someone (possibly you) added a script to the page and made a mistake.
... more things to check we have listed a few simple ways to check that your website works properly, as well as the most common errors you may run across and how to fix them.

Client-side tooling overview - Learn web development
linters linters are tools that check through your code and tell you about any errors that are present, what error types they are, and what code lines they are present on.
... often linters can be configured to not only report errors, but also report any violations of a specified style guide that you team might be using (for example code that is using the wrong number of spaces for indentation, or using template literals rather than regular string literals).
... eslint is the industry standard javascript linter — a highly configurable tool for catching potential syntax errors and encouraging "best practices" throughout your code.
... code formatters code formatters are somewhat related to linters, except that rather than point out errors in your code, they usually tend to make sure your code is formatted correctly, according to your style rules, ideally automatically fixing errors that they find.

Android-specific test suites
android-findbugs ensures that the code avoids common java coding errors.
... android-lint ensures that the code avoids common android coding errors.
... android-findbugs ensures that the code avoids common java coding errors.
... android-lint ensure that the code avoids common android coding errors.

JSAPI User Guide
errors and exceptions the importance of checking the return value of jsapi functions, of course, goes without saying.
... error reports todo your custom errorreporter todo when errors are reported automatic handling of uncaught exceptions the js_compile*, js_call*, js_execute*, and js_evaluate* functions automatically pass exceptions to the error reporter in certain cases.
... uncatchable errors another way for a jsnative callback to report an error is like this: if (!p) { js_reportoutofmemory(cx); return false; } this does something subtly different from what js_reporterror does.
... most errors, including those raised by js_reporterror, are represented as javascript exceptions and thus interact with the javascript exception-handling language features, try, catch, and finally.

nsIXULTemplateBuilder
errors throws ns_error_null_pointer if aresult or aquerynode is null.
...void removeresult( in nsixultemplateresult aresult ); parameters aresult the result to remove errors throws ns_error_null_pointer if aresult is null replaceresult() inform the template builder that one result should be replaced with another.
... errors throws ns_error_null_pointer if either argument is null, or ns_error_invalid_arg if the ids don't match resultbindingchanged() informs the template builder that one or more of the optional bindings for a result has changed.
...void resultbindingchanged( in nsixultemplateresult aresult ); parameters aresult the result to change errors throws ns_error_null_pointer if aresult is null getresultforid() returns the result for a given id.

Introduction to the File and Directory Entries API - Web APIs
it also describes restrictions that raise security errors if you ignore them.
...at minimum, handle the errors to provide error messages, so you'll have an idea of what's going on.
...if you ignore them, you will get security errors.
...if you do so, the browser throws errors or your app fails silently.

Payment Request API - Web APIs
dictionaries addresserrors a dictionary containing strings providing descriptive explanations of any errors in any paymentaddress entries which have errors.
... payererrors a dictionary containing strings providing descriptive explanations of any errors in related to paymentresponse's email, phone, and name attributes.
... basiccarderrors an object providing any error messages associated with the fields in the basiccardresponse object that are not valid.
... this is used as the value of the paymentmethod property on the paymentvalidationerrors object sent to the paymentrequest when an error occurs.

WebGL constants - Web APIs
errors constants returned from webglrenderingcontext.geterror().
...returns false if there were errors.
...returns false if errors were found.
...returns false if errors occurred.

How to check the security state of an XMLHTTPRequest over SSL - Web APIs
const {cc,ci} = require("chrome"); function createtcperrorfromfailedxhr(xhr) { let status = xhr.channel.queryinterface(ci.nsirequest).status; let errtype; if ((status & 0xff0000) === 0x5a0000) { // security module const nsinsserrorsservice = ci.nsinsserrorsservice; let nsserrorsservice = cc['@mozilla.org/nss_errors_service;1'].getservice(nsinsserrorsservice); let errorclass; // geterrorclass will throw a generic ns_error_failure if the error code is // somehow not in the set of covered errors.
... try { errorclass = nsserrorsservice.geterrorclass(status); } catch (ex) { //catching security protocol exception errorclass = 'securityprotocol'; } if (errorclass == nsinsserrorsservice.error_class_bad_cert) { errtype = 'securitycertificate'; } else { errtype = 'securityprotocol'; } // nss_sec errors (happen below the base value because of negative vals) if ((status & 0xffff) < math.abs(nsinsserrorsservice.nss_sec_error_base)) { // the bases are actually negative, so in our positive numeric space, we // need to subtract the base off our value.
... let nsserr = math.abs(nsinsserrorsservice.nss_sec_error_base) - (status & 0xffff); switch (nsserr) { case 11: // sec_error_expired_certificate, sec(11) errname = 'securityexpiredcertificateerror'; break; case 12: // sec_error_revoked_certificate, sec(12) errname = 'securityrevokedcertificateerror'; break; // per bsmith, we will be unable to tell these errors apart very soon, // so it makes sense to just folder them all together already.
...) errname = 'securityinadequatekeyusageerror'; break; case 176: // sec_error_cert_signature_algorithm_disabled, sec(176) errname = 'securitycertificatesignaturealgorithmdisablederror'; break; default: errname = 'securityerror'; break; } } else { // calculating the difference let sslerr = math.abs(nsinsserrorsservice.nss_ssl_error_base) - (status & 0xffff); switch (sslerr) { case 3: // ssl_error_no_certificate, ssl(3) errname = 'securitynocertificateerror'; break; case 4: // ssl_error_bad_certificate, ssl(4) errname = 'securitybadcertificateerror'; break; case 8: // ssl_error_unsupported_certificate_type, ssl(8) errname = ...

HTTP Index - HTTP
21 cors errors cors, errors, http, https, messages, same-origin, security, console, troubleshooting cross-origin resource sharing (cors) is a standard that allows a server to relax the same-origin policy.
... 22 reason: cors disabled authentication, authentication article, cors, cross-origin, disabled, errors, http, https, messages, resource, same origin, same-origin, security, sharing, validation, secure, troubleshooting a request that needs to use cors was attempted, but cors is disabled in the user's browser.
...for workers, non-compliant requests are treated as fatal network errors by the user agent.
...responses are grouped in five classes: informational responses (100–199),successful responses (200–299),redirects (300–399),client errors (400–499),and server errors (500–599).

JavaScript modules - JavaScript
with a file:// url), you'll run into cors errors due to javascript module security requirements.
...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.
...too; if we tried to import different functions of the same name into the same top-level module file, we'd end up with conflicts and errors.
...with a file:// url), you'll run into cors errors due to javascript module security requirements.

Chapter 5: Let's build a Firefox extension - Archive of obsolete content
true javascript.options.showinconsole (present in firefox 3.5+) outputs javascript errors to the error console.
... if your extension isn’t working according to plan, first see if there’s an error being displayed on the errors panel of the error console.
... if you set things up as recommended in the section “setting up your development environment”, xul and javascript errors will appear here.

Moving, Copying and Deleting Files - Archive of obsolete content
a number of errors could occur when copying a file, for instance if the file to copy does not exist or the destination directory is not writable.
... it is a good idea to enclose file operations within a try-catch block in order to capture any errors that might occur.
... for a list of possible file related errors, see file errors.

Adding Event Handlers - Archive of obsolete content
by default the javascript console only shows errors from web content.
... to show errors in chrome javascript, it is necessary to change the preference javascript.options.showinconsole to true.
...by setting this value to true, non-standard, poorly written, or syntax prone to cause logic errors are logged to the javascript console.

Using the W3C DOM - Archive of obsolete content
some browsers have non-standard properties, such as internet explorer's document.all[], that are not part of the w3c document object model (dom) standards and may cause javascript errors in standards-compliant browsers.
....all.id_attribute_value document.all[id_attribute_value] the following form related properties (originally from internet explorer) are not supported in the w3c document object model: formname.inputname.value inputname.value formctrlname document.forms(0) (note: document.forms[0] (using square brackets) uses the dom standard forms collection) scripts that use these properties will throw errors in most standards-compliant browsers.
... css 1 forward-compatible parsing css 2.1 rules for handling parsing errors changing an element's text using the dom the text of an element is available as the textcontent or innertext property (some browsers support both).

WAI-ARIA basics - Learn web development
at the end of this section we showed that we have included some aria attributes on the error message box that displays any validation errors when you try to submit the form: <div class="errors" role="alert" aria-relevant="all"> <ul> </ul> </div> role="alert" automatically turns the element it is applied to into a live region, so changes to it are read out; it also semantically identifies it as an alert message (important time/context sensitive information), and represents a better, more accessible way of delivering an alert to...
...when errors are added or removed.
... this is useful because the user will want to know what errors are left, not just what has been added or removed from the list.

What are browser developer tools? - Learn web development
it allows you to run lines of javascript against the page currently loaded in the browser, and reports the errors encountered as the browser tries to execute your code.
... alert('hello!); document.cheeseselector('html').style.backgroundcolor = 'purple'; const mywordmark = document.createelement('img'); mybanana.setattribute('src','https://blog.mozilla.org/press/wp-content/themes/onemozilla/img/mozilla-wordmark.png'); document.queryselector('h1').appendchild(mywordmark); you'll start to see the kind of errors that the browser returns.
... often these errors are fairly cryptic, but it should be pretty simple to figure these problems out!

Making asynchronous programming easier with async and await - Learn web development
status: ${response.status}`); } else { return await response.blob(); } } myfetch().then((blob) => { let objecturl = url.createobjecturl(blob); let image = document.createelement('img'); image.src = objecturl; document.body.appendchild(image); }) .catch((e) => console.log(e) ); this is because the .catch() block will catch errors occurring in both the async function call and the promise chain.
... if you used the try/catch block here, you might still get unhandled errors in the myfetch() function when it's called.
... for error handling, we've included a .catch() block on our displaycontent() call; this will handle errors ocurring in both functions.

Graceful asynchronous programming with Promises - Learn web development
using asynchronous promises instead, we'd end up with something like this: choosetoppings() .then(function(toppings) { return placeorder(toppings); }) .then(function(order) { return collectorder(order); }) .then(function(pizza) { eatpizza(pizza); }) .catch(failurecallback); this is much better — it is easier to see what is going on, we only need a single .catch() block to handle all the errors, it doesn't block the main thread (so we can keep playing video games while we wait for the pizza to be ready to collect), and each operation is guaranteed to wait for previous operations to complete before running.
...fetch promises do not fail on 404 or 500 errors — only on something catasrophic like a network failure.
... responding to failure something is missing — currently, there is nothing to explicitly handle errors if one of the promises fails (rejects, in promise-speak).

Debugging Frame Reflow
other reflow debug options gecko_display_reflow_flag_pixel_errors setting this option via set gecko_display_reflow_flag_pixel_errors = 1 enables a verification for each coordinate value that the coordinates are aligned at pixel boundaries.
... block 0268a764 r=0 a=uc,uc c=uc,uc cnt=872 block 0268a764 d=0,0 me=0 cell 0268a6c0 d=0,0 me=0 row 0268a594 d=uc,20 value 20 is not a whole pixel rowg 0268a02c d=uc,695 value 695 is not a whole pixel while unaligned values at the entrance of a frame reflow can be ignored, when they appear at the exit of a routine this can cause display errors like stray lines.
... os2 is very vulnerable to pixel alignment errors as text is drawn on pixel boundaries.

Debugging JavaScript
this shows any javascript errors in your app, as well as any logging calls from the console api.
... browser console the browser console lets you see all javascript errors and logging in the browser, including from firefox code.
...(the pref also warns on common javascript idioms that are not errors).

ESLint
this lets you see errors in real time, and can help you fix issues before you compile or run tests, reducing the time to develop patches.
... understanding rules and errors not all files are linted currently eslint runs on: .js .jsx .jsm .xml .html .xhtml additionally, some directories and files are ignored, see the .eslintignore file handling errors if your code fails an eslint rule, you'll get an error similar to this: /gecko/toolkit/mozapps/installer/js-compare-ast.js 18:39 error 'snarf' is not defined.
... for example: in windows 10, if you have installed node.js on "c:\nodejs", then the command should look like: export path=$path:/c/nodejs enabling eslint for a new directory remove the directory from .eslintignore (in the base directory of the repository) fix errors that occur when running ./mach eslint path/to/dir, see also the no-undef rules below.

Assert.jsm
undefined throws( block, expected, message ); parameters block function block to evaluate and catch eventual thrown errors expected test reference to evaluate against the thrown result from block message short explanation of the expected result rejects() expected to reject a promise.
... promise rejects( promise, expected, message ); parameters promise promise promise to wait for rejection and catch eventual thrown errors expected test reference to evaluate against the thrown result from block message short explanation of the expected result greater() the greater than assertion tests two numbers with the > operator.
... this report method only throws errors on assertion failures, as per spec, but consumers of this module (think: xpcshell-test, mochitest) may want to override this default implementation.

Log.jsm
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.
... error other runtime errors or unexpected conditions.
... warn use of deprecated apis, poor use of api, 'almost' errors, other runtime situations that are undesirable or unexpected, but not necessarily "wrong".

Promise
note: you should always handle, forward, or report errors (rejection reasons).
...see handling errors and common pitfalls below.
... handling errors and common pitfalls you should report unhandled errors, unless you're handing off the promise to a caller or another code path that will handle the error.

javascript.options.showInConsole
the preference javascript.options.showinconsole controls whether errors or warnings in chrome code are shown in the error console.
... 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.
... true (default) errors and warnings from both chrome and content are shown in the error console.

javascript.options.strict
javascript warnings are generated when code is executed that doesn't cause a run-time error, but is non-standard, poorly written, or prone to cause logic errors.
... var name2= "peter"; document.getelementbyid("sample").innerhtml = name1; </script> </body> </html> possible values and their effects: true: show javascript errors and warnings.
... false: show javascript errors only.

NSS API Guidelines
errors, though not integers, are done as external constants, instead of preprocessor definitions.
...likewise, the external references to errors are made in the prototypes files, with the functions which can return them.
...usually, every public routine has a private counterpart, and the implementation of the public routine looks like this: nssimplement rv * nsstype_method ( nsstype *t, nssfoo *arg1, nssbar *arg2 ) { nss_clearerrorstack(); #ifdef debug if( !nssfoo_verifypointer(arg1) ) return (rv *)null; if( !nssbar_verifypointer(arg2) ) return (rv *)null; #endif /* debug */ return nsstype_method(t, arg1, arg2); } aside from error cases, all documented entry points should check pointers in a debug, wherever possible.

NSS_3.12.3_release_notes.html
new in nss 3.12.3 changes in behavior: in the development of nss 3.12.3, it became necessary to change some old library behaviors due to the discovery of certain vulnerabilities in the old behaviors, and to correct some errors that had limited nss's ability to interoperate with cryptographic hardware and software from other sources.
...essages need distinct types bug 438870: free freebl hashing code of dependencies on nspr and libutil bug 439115: db merge allows nickname conflicts in merged db bug 439199: sse2 instructions for bignum are not implemented on windows 32-bit bug 441321: tolerate incorrect encoding of dsa signatures in ssl 3.0 handshakes bug 444404: libpkix reports unknown issuer for nearly all certificate errors bug 452391: certutil -k incorrectly reports ec private key as an orphan bug 453234: support for seed cipher suites to tls rfc4010 bug 453364: improve pk11_cipherop error reporting (was: pk11_createcontextbysymkey returns null bug 456406: slot list leaks in symkeyutil bug 461085: rfe: export function cert_comparecerts bug 462293: crash on fork after softoken is dlclose'd on some unix p...
...479601: wrong type (utf8 string) for email addresses in subject by cert_asciitoname bug 480142: use sizeof on the correct type of ckc_x509 in lib/ckfw bug 480257: ocsp fails when response > 1k byte bug 480280: the cka_ec_point pkcs#11 attribute is encoded in the wrong way: missing encapsulating octet string bug 480442: remove (empty) watcomfx.h from nss bug 481216: fix specific spelling errors in nss bug 482702: ocsp test with revoked ca cert validated as good.

nsIJumpListBuilder
lists are built in real-time during the sequence of build calls, make sure to check for errors on each individual step.
...exceptions thrown ns_error_unexpected on internal errors.
...exceptions thrown ns_error_unexpected on internal errors.

Testing Mozilla code
asan nightly projectthe asan nightly project involves building a firefox nightly browser with the popular addresssanitizer tool and enhancing it with remote crash reporting capabilities for any errors detected.clang static analysisthis document is split in two parts.
... 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.
...this type of coverage is only concerned with hit counts for lines and branches.the valgrind test jobthe valgrind test job builds the browser and runs it under valgrind, which can detect various common memory-related errors.

Migrating from Firebug - Firefox Developer Tools
while there are no breakpoints for single javascript errors, there is a setting pause on exceptions within the debugger panel options.
... developer toolbar display of error count when there are javascript errors on a page, the firebug start button shows a badge with their number.
... the devtools show the number of errors in the developer toolbar.

LocalFileSystem - Web APIs
//taking care of the browser-specific prefix window.requestfilesystem = window.requestfilesystem || window.webkitrequestfilesystem; // the first parameter defines the type of storage: persistent or temporary // next, set the size of space needed (in bytes) // initfs is the success callback // and the last one is the error callback // for denial of access and other errors.
... opt_errorcallback the error callback that is called when errors happen or when the request to obtain the file system is denied.
... errorcallback the error callback that is called when errors happen or when the request to obtain the entry object is denied.

MediaRecorder.onerror - Web APIs
you can provide an event handler to deal with errors that occur while creating or using a media recorder.
...in addition to other general errors that might occur, the following errors are specifically possible when using the mediastream recording api; to determine which occurred, check the value of mediarecordererrorevent.error.name.
... these errors may occur either directly because of a call to a mediarecorder method, or indirectly due to a problem arising during the recording process.

MediaRecorder.start() - Web APIs
exceptions errors that can be detected immediately are thrown as dom exceptions.
... all other errors are reported through error events sent to the mediarecorder object.
... you can implement the onerror event handler to respond to these errors.

RTCPeerConnection: icecandidateerror event - Web APIs
these errors occur only when the connection's ice gathering state is gathering.
... example the following example establishes a handler for icecandidateerrors that occur on the rtcpeerconnection pc.
... this handler looks specifically for 701 errors that indicate that candidates couldn't reach the stun or turn server.

RTCPeerConnection.setRemoteDescription() - Web APIs
operationerror any errors that occur which don't match the others specifeid here are reported as operationerror.
... this includes identity validation errors.
...this happens instead of throwing an exception, thereby reducing the number of potential errors which might occur, and simplifies the processing you need to do when you receive an offer, by eliminating the need to handle the offer/answer process differently depending on whether the local peer is the caller or callee.

ReadableStream.pipeTo() - Web APIs
the pipeto() method of the readablestream interface pipes the current readablestream to a given writablestream and returns a promise that fulfills when the piping process completes successfully, or rejects if any errors were encountered.
... preventabort: if this is set to true, errors in the source readablestream will no longer abort the destination writablestream.
... preventcancel: if this is set to true, errors in the destination writablestream will no longer cancel the source readablestream.

Signaling and video calling - Web APIs
handling getusermedia() errors if the promise returned by getusermedia() concludes in a failure, our handlegetusermediaerror() function performs.
... once the answer has been created using mypeerconnection.createanswer(), the description of the local end of the connection is set to the answer's sdp by calling mypeerconnection.setlocaldescription(), then the answer is transmitted through the signaling server to the caller to let them know what the answer is any errors are caught and passed to handlegetusermediaerror(), described in handling getusermedia() errors.
...this prevents stray event handlers from being triggered while the connection is in the process of closing, potentially causing errors.

WindowOrWorkerGlobalScope.fetch() - Web APIs
the promise does not reject on http errors — it only rejects on network errors.
... you must use then handlers to check for http errors.
...a fetch() promise does not reject on http errors (404, etc.).

Cognitive accessibility - Accessibility
input assistance guidelines aim to reduce the likelihood that users, especially those with disabilities, make a mistake, and, if they do make a mistake, increase the likelihood that they see and comprehend the error message and can successfully fix any errors.
...if multiple errors are present, provide a summary, with each error linking to the related input.
... data entered by the user should be checked for errors before submission, and the user should be given the opportunity to correct them.

<input>: The Input (Form Input) element - HTML: Hypertext Markup Language
several errors could occur, including a rangeunderflow error if the value is less than 2, rangeoverflow if greater than 10, stepmismatch if the value is a number between 2 and 10, but not an even integer (does not match the requirements of the step attribute), or typemismatch if the value is not a number.
...this is particularly useful for dates and times, such as when you want to allow the range to be from 8 pm to 8 am: <input type="time" min="20:00" max="08:00" name="overnight"> specific attributes and their values can lead to a specific error validitystate: validity object errors depend on the <input> attributes and their values: attribute relevent property description max validitystate.rangeoverflow occurs when the value is greater than the maximum value as defined by the max attribute maxlength validitystate.toolong occurs when the number of characters is greater than the number allowed by the maxlength property m...
... in addition to the errors described in the table above, the validitystate interface contains the badinput, valid, and customerror boolean readonly properties.

Network Error Logging - HTTP
dns.failed request to the dns server failed due to reasons not covered by previous errors (e.g.
...erver timed out tcp.closed the tcp connection was closed by the server tcp.reset the tcp connection was reset tcp.refused the tcp connection was refused by the server tcp.aborted the tcp connection was aborted tcp.address_invalid the ip address is invalid tcp.address_unreachable the ip address is unreachable tcp.failed the tcp connection failed due to reasons not covered by previous errors http.error the user agent successfully received a response, but it had a 4xx or 5xx status code http.protocol.error the connection was aborted due to an http protocol error http.response.invalid response is empty, has a content-length mismatch, has improper encoding, and/or other conditions that prevent user agent from processing the response http.response.redirect_loop the request was ab...
...orted due to a detected redirect loop http.failed the connection failed due to errors in http protocol not covered by previous errors specifications specification network error logging ...

Control flow and error handling - JavaScript
while it is common to throw numbers or strings as errors, it is frequently more effective to use one of the exception types specifically created for this purpose: ecmascript exceptions domexception and domerror throw statement use the throw statement to throw an exception.
...(1 = jan, 12 = dec) let months = ['jan', 'feb', 'mar', 'apr', 'may', 'jun', 'jul', 'aug', 'sep', 'oct', 'nov', 'dec']; if (months[mo]) { return months[mo]; } else { throw 'invalidmonthno'; // throw keyword is used here } } try { // statements to try monthname = getmonthname(mymonth); // function could throw exception } catch (e) { monthname = 'unknown'; logmyerrors(e); // pass exception object to error handler (i.e.
... 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.

AggregateError() constructor - JavaScript
the aggregateerror() constructor creates an error for several errors that need to be wrapped in a single error.
... syntax new aggregateerror(errors[, message]) parameters errors an iterable of errors, may not actually be error instances.
... examples creating an aggregateerror try { throw new aggregateerror([ new error("some error"), ], 'hello'); } catch (e) { console.log(e instanceof aggregateerror); // true console.log(e.message); // "hello" console.log(e.name); // "aggregateerror" console.log(e.errors); // [ error: "some error" ] } specifications specification promise.anythe definition of 'aggregateerror()' in that specification.

AggregateError - JavaScript
the aggregateerror object represents an error when several errors need to be wrapped in a single error.
... it is thrown when multiple errors need to be reported by an operation, for example by promise.any(), when all promises passed to it reject.
... examples catching an aggregateerror promise.any([ promise.reject(new error("some error")), ]).catch(e => { console.log(e instanceof aggregateerror); // true console.log(e.message); // "all promises rejected" console.log(e.name); // "aggregateerror" console.log(e.errors); // [ error: "some error" ] }); creating an aggregateerror try { throw new aggregateerror([ new error("some error"), ], 'hello'); } catch (e) { console.log(e instanceof aggregateerror); // true console.log(e.message); // "hello" console.log(e.name); // "aggregateerror" console.log(e.errors); // [ erro...

Promise - JavaScript
comprehension is enhanced by seeing the errors actually occur.
... to force more errors, change the threshold values.
... "use strict"; // to experiment with error handling, "threshold" values cause errors randomly const threshold_a = 8; // can use zero 0 to guarantee error function tetheredgetnumber(resolve, reject) { try { settimeout( function() { const randomint = date.now(); const value = randomint % 10; try { if(value >= threshold_a) { throw new error(`too large: ${value}`); } } catch(msg) { reject(`error in callback ${msg}`); } resolve(value); return; }, 500); // to experiment with error at set-up, uncomment the following 'throw'.

Chapter 6: Firefox extensions and XUL applications - Archive of obsolete content
init: function() { this.stack = new array(); }, push: function(val) { this.stack.push(number(val)); }, _letfunc: function(func) { a = this.pop(); b = this.pop(); this.push(func(a, b)); }, plus: function() { return this._letfunc(this._plus); }, _plus: function(a, b) { return a + b; }, pop: function() { return this.stack.pop(); } } check for errors now you’re ready for your first test.
...relative paths will throw errors.

Setting Up a Development Environment - Archive of obsolete content
the firefox error console (tools > error console) normally displays javascript errors that occur on web pages, but with some tweaking you can get error information from your extension.
...one of the most common errors developers make is to register a js event listener or observer, and never removing it.

The Essentials of an Extension - Archive of obsolete content
any errors or missing information will cause the installation process to fail, or the extension to be installed in a disabled state.
...you may get weird parsing errors or incorrect localization if you don't get this right.

Exception logging in JavaScript - Archive of obsolete content
this had the unintended consequence of logging "expected" errors at length into the console.
... all other errors are reported when the last javascript frame on the stack returns to a c++ caller without handling the exception.

Migrate apps from Internet Explorer to Mozilla - Archive of obsolete content
the first tool is the built-in javascript console, shown in figure 1, where errors and warnings are logged.
...javascript console the javascript console can show the full log list or just errors, warnings, and messages.

Porting NSPR to Unix Platforms - Archive of obsolete content
<tt>mozilla/nsprpub/pr/src/md/unix/netbsd.c</tt> you need to modify the following existing files: <tt>mozilla/nsprpub/pr/include/md/makefile</tt> <tt>mozilla/nsprpub/pr/include/md/_unixos.h</tt>: just fix the compiling errors, usually pointed out by the <tt>#error</tt> preprocessor directives we inserted.
... <tt>mozilla/nsprpub/pr/include/md/prosdep.h</tt> <tt>mozilla/nsprpub/pr/src/md/prosdep.c</tt> <tt>mozilla/nsprpub/pr/src/md/unix/makefile</tt> <tt>mozilla/nsprpub/pr/src/md/unix/objs.mk</tt> <tt>mozilla/nsprpub/pr/src/md/unix/unix.c</tt>: just fix the compiling errors, usually pointed out by the <tt>#error</tt> preprocessor directives we inserted for a pthreads port, you need to modify the following files: <tt>mozilla/nsprpub/pr/include/md/_pth.h</tt> files in mozilla/nsprpub/pr/src/pthreads, most likely <tt>ptthread.c</tt> and <tt>ptio.c</tt> testing your port we have some unit tests in <tt>mozilla/nsprpub/pr/tests</tt>.

Frequently Asked Questions - Archive of obsolete content
this is an xml debugging message to help xml authors correct errors in their xml documents.
...(it doesn't mean there's an error in mozilla.) there are many different xml errors, but the most common one in svg files is "xml parsing error: prefix not bound to a namespace".

Reading from Files - Archive of obsolete content
in fact, it is a good idea to enclose file reading and writing operations within a try-catch block to capture any errors that might occur during the process.
... see file errors for a list of errors that might occur.

Writing to Files - Archive of obsolete content
in this example, the operations are enclosed in a try-catch block in order to capture any errors that might occur during the process.
... see file errors for a list of errors that might occur.

Additional Install Features - Archive of obsolete content
handling errors you will likely want to handle errors gracefully.
...it will also show any errors that occured.

XUL accessibility guidelines - Archive of obsolete content
provide users with clear instruction and feedback, and allow users to correct errors.
...ensure the user is informed of any user based errors and that instruction and opportunity for reperforming error causing actions is allowed.

Building XULRunner with Python - Archive of obsolete content
development machine setup first a word of warning that zonealarm has exhibited memory leaks that cause build machines to crash with rather spurious errors.
...don't copy any.pyo files that exist for python modules in the application or errors will occur on the target machine.

Archived Mozilla and build documentation - Archive of obsolete content
error console the error console is a tool available in most mozilla-based applications that is used for reporting errors in the application chrome and in web pages user opens.
... it reports javascript-related errors and warnings, css errors and arbitrary messages from chrome code.

Gecko Compatibility Handbook - Archive of obsolete content
correct any errors and replace proprietary code wherever possible.
... upgrade web authoring tool to versions that support the w3 standards and gecko browsers content differs in gecko browsers and internet explorer the javascript console in netscape 6.x and netscape 7.x displays errors about document.all, document.layers, document.<property> not being defined because of an incorrect browser sniffing, or use of proprietary javascript.

Mozilla release FAQ - Archive of obsolete content
regarding shells, i would like to recommend the following: if you are using unix, use bash-family shells for the build because of the better control over redirection (in case you want to log errors and messages) if you are using win32, using the default shell cmd.exe (as opposed to 4dos or 4nt) will probably yield better results.
...i get library errors in dist/bin there's a script called mozilla.

Sunbird Theme Tutorial - Archive of obsolete content
to detect errors, choose tools – javascript console...
... the javascript console window displays css errors, not just javascript errors.

Using IO Timeout And Interrupt On NT - Archive of obsolete content
these two errors are generated by the nspr layer, so the os is oblivious of what is going on and the overlapped io request is still in progress.
...when we stop supporting nt 3.51, we can look into using nt 4's <tt>cancelio()</tt> function to cancel outstanding overlapped io requests when we get io timeout or interrupt errors.

Common causes of memory leaks in extensions - Extensions
while bug 695480 should prevent most of these compartment leaks, add-ons still need to be aware of the practices that caused these leaks, as the fix causes many add-ons which would have otherwise caused a leak to instead throw errors when attempting to access nodes from documents which no longer exist.
... components.utils.unload("chrome://myaddon/content/mymodule.jsm"); } note: modules not belonging to your add-on — such as services.jsm — should not be unloaded by your add-on, as this might cause errors and/or performance regressions and will actually increase the memory usage.

Packet - MDN Web Docs Glossary: Definitions of Web-related terms
error detection and correction error detection and correction are codes that are used to detect and apply corrections to the errors that occur when data is transmitted to the receiver.
...forward error correction is when the receiver uses the error-correcting code which automatically corrects the errors at the transmitter, the calculation is performed before the packet is sent.

Syntax error - MDN Web Docs Glossary: Definitions of Web-related terms
syntax errors are detected while compiling or parsing source code.
... browser development tools display javascript and css syntax errors in the console.

Debugging CSS - Learn web development
browsers expect your css and html to be correctly written, however browsers are also very forgiving and will try their best to display your webpages even if you have errors in the markup or stylesheet.
...a good first step therefore is to run your html and css through a validator, to pick up and fix any errors.

Client-side form validation - Learn web development
note: there are several errors that will prevent the form from being submitted, including a badinput, patternmismatch, rangeoverflow or rangeunderflow, stepmismatch, toolong or tooshort, typemismatch, valuemissing, or a customerror.
...if you want to dig into form validation ui requirements, here are some useful articles you should read: smashingmagazine: form-field validation: the errors-only approach smashingmagazine: web form validation: best practices and tutorials six revision: best practices for hints and validation in web forms a list apart: inline validation in web forms an example that doesn't use the constraint validation api in order to illustrate this, the following is a simplified version of the previous example that works with legacy browsers.

Choosing the right approach - Learn web development
failure callbacks need to be called once for each level of nesting, whereas with promises you can just use a single .catch() block to handle the errors for the entire chain.
... when your code has the potential to take longer to run than the time interval you’ve assigned, it’s better to use recursive settimeout() — this will keep the time interval constant between executions regardless of how long the code takes to execute, and you won't get errors.

Cooperative asynchronous JavaScript: Timeouts and intervals - Learn web development
you'll probably want a way to stop such tasks, otherwise you may end up getting errors when the browser can't complete any further versions of the task, or if the animation being handled by the task has finished.
... when your code has the potential to take longer to run than the time interval you’ve assigned, it’s better to use recursive settimeout() — this will keep the time interval constant between executions regardless of how long the code takes to execute, and you won't get errors.

Storing the information you need — Variables - Learn web development
you shouldn't use other characters because they may cause errors or be hard to understand for an international audience.
...browsers recognize them as different code items, and so you'll get errors.

Solve common problems in your JavaScript code - Learn web development
one of the most common errors is to declare the function, but not call it anywhere.
...also, see other common errors for a description of common errors.

Getting started with Vue - Learn web development
this will help us catch common errors, but not be overly opinionated.
...this will check for errors when we save a file inside the project.

Handling common accessibility problems - Learn web development
tenon: another nice online tool that goes through the code at a provided url and returns results on accessibility errors including metrics, specific errors along with the wcag criteria they affect, and suggested fixes.
...like the others, it checks pages and returns accessibility errors.

Configuring Build Options
this will help catch any errors introduced into the js code, with less of a performance impact compared to the --enable-debug option.
...after enabling the crash reporter in your local build, you will need to run mach with the --enable-crash-reporter (note the extra dash) to enable it at runtime, like so: `./mach run --enable-crash-reporter` ac_add_options --enable-warnings-as-errors this makes compiler warnings into errors which fail the build.

Old Thunderbird build
on linux, this can manifest as problems setting up the virtualenv for running tests (failure to install pip or virtualenv because of os access denied errors, where access is denied not because of permission problems, but because the paths being accessed have been truncated, and so do not exist).
... if on windows you get link errors like "lnk1102: out of memory" or "lnk1318: unexpected pdb error; ok (0)", try deleting the largest .pdb files before rushing out the door to buy more ram.

Simple Thunderbird build
on linux, this can manifest as problems setting up the virtualenv for running tests (failure to install pip or virtualenv because of os access denied errors, where access is denied not because of permission problems, but because the paths being accessed have been truncated, and so do not exist).
... if on windows you get link errors like "lnk1102: out of memory" or "lnk1318: unexpected pdb error; ok (0)", try deleting the largest .pdb files before rushing out the door to buy more ram.

Using the Browser API
prev.disabled = true; next.disabled = true; searchbar.value = ''; } } }); note that whenever one of the search-related methods is invoked, a mozbrowserfindchange event is fired to allow you to react to search changes in a more precise way if desired: //browser.addeventlistener('mozbrowserfindchange', function(e) { // can react to find changes if required //}) reporting errors we've got one more piece of code to mention from our source: browser.addeventlistener('mozbrowsererror', function (e) { console.log("loading error: " + e.detail); }); this simple listener logs an error message to the console when an error with the browser iframe is encountered.
... note that this doesn't include simple errors due to incorrect urls being entered.

Implementing QueryInterface
it addrefs the resulting interface, not this, thus following the com-correct way (particularly important in aggregation) it uses nscomtypeinfo<t>::getiid() instead of ktiid thus saving a global declaration and global space it uses c 's static_cast, via ns_static_cast, which detects errors when you can't really get to the desired interface.
... it tests for bad input with an ns_assertion, to find logic errors immediately in debug builds.

Following the Android Toasts Tutorial from a JNI Perspective
we want to wrap this in a try-catch statement so if any errors occur we make sure to unload the classes and the java environment, this is good for performance.
...because we don't want to keep typing string signatures everywhere, we can end up with typos and hard to trace back errors, we use the sig object.

Sqlite.jsm
the error may have an errors property.
... if defined, it will be an array of objects describing individual errors.

Localization content best practices
if you're reviewing a patch, check also strings for grammar errors, capitalization or inconsistencies.
... test localizability as a developer, you should always test your patches not just for code errors, but also for localizability issues in case they involve string or ui changes.

Localization formats
diffs .lang files will be cached which will reduce any slowness effect disadvantage to .lang no plural forms no context for localizers unless you provide good comments no styling by localizers if it is needed may be slower because file is not compiled into binaries not used as a standard by any other localization project no tools to validate syntax, so a localizer may cause accidental errors that can cause breakage (level of breakage depends on level of error) cannot use po editor, which most localizers know and love gettext (.po) gettext is a widely-used localization format that uses .po files.
... without having the exact content as the msgid, this process may cause several errors since the localizers cannot has to continually switch back-and-forth.

What every Mozilla translator should know
when you create a bug, if you want the person in charge of the l10n to follow up your bug you should cc: l10n@mozilla.com if you choose to make changes to your localization, you should make the changes local to your disk, push them to your hg repository on merucial, test the changes on a nightly/tinderbox build, fix any errors if some are found and test again, and send the new changeset id as your "opt-in" revisions to the l10-drivers.
... l10n tinderbox when the color is green, it means that the build process has finished with no errors.

L20n Javascript API
these errors include: context.runtimeerror, when an entity is missing or broken in all supported locales; in this case, l20n will show the the best available fallback of the requested entity in the ui: the source string as found in the resource, or the identifier.
...when fetching a resource file, or recursive import statements in resource files), context.translationerror, when there is a missing translation in one of supported locales; the context instance will try to retrieve a fallback translation from the next locale in the fallback chain, compiler.error, when l20n is unable to evaluate an entity to a string; there are two types of errors in this category: compiler.valueerror, when l20n can still try to use the literal source string of the entity as fallback, and compiler.indexerror otherwise.

PRErrorCode
you can also set your own errors using pr_seterror.
... for nspr errors, see error codes.

NSS CERTVerify Log
defined in certt.h: /* * this structure is used to keep a log of errors when verifying * a cert chain.
... this allows multiple errors to be reported all at * once.

NSS 3.12.4 release notes
bug 427135: add super-h (sh3,4) architecture support bug 431958: improve des and sha512 for x86_64 platform bug 433791: win16 support should be deleted from nss bug 449332: secu_parsecommandline does not validate its inputs bug 453735: when using cert9 (sqlite3) db, set or change master password fails bug 463544: warning: passing enum* for an int* argument in pkix_validate.c bug 469588: coverity errors reported for softoken bug 470055: pkix_httpcertstore_findsocketconnection reuses closed socket bug 470070: multiple object leaks reported by tinderbox bug 470479: io timeout during cert fetching makes libpkix abort validation.
... bug 470500: firefox 3.1b2 crash report [[@ nssutil3.dll@0x34c0 ] bug 482742: enable building util independently of the rest of nss bug 483653: unable to build certutil.exe for fennec/wince bug 485145: miscellaneous crashes in signtool on windows bug 485155: nss_enable_pkix_verify=1 causes sec_error_unknown_issuer errors bug 485527: rename the _x86_ macro in lib/freebl bug 485658: vfychain -p reports revoked cert bug 485745: modify fipstest.c to support cavs 7.1 drbg testing bug 486304: cert7.db/cert8.db corruption when importing a large certificate (>64k) bug 486405: allocator mismatches in pk12util.c bug 486537: disable execstack in freebl x86_64 builds on linux bug 486698: facilitate the building of major components independently and in a chain manner by downstream distributions bug 486999: c...

sslerr.html
from the supplied url." ssl_error_unrecognized_name_alert -12182 "ssl peer has no certificate for the requested dns name." ssl_error_bad_cert_status_response_alert -12181 "ssl peer was unable to get an ocsp response for its certificate." ssl_error_bad_cert_hash_value_alert -12180 "ssl peer reported bad certificate hash value." unspecified errors that occurred while attempting some operation: all the error codes in the following block describe the operation that was being attempted at the time of the unspecified failure.
... these failures may be caused by the system running out of memory, or errors returned by pkcs#11 routines that did not provide meaningful error codes of their own.

Installing Pork
if you run simply "make install" and see file permission errors, mcpp is likely trying to override your main gcc installation.
...a 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.

Index
these operations are infallible, so required slots must be pre-allocated, or implementations must suppress out-of-memory errors.
... 433 js_reporterror jsapi reference, spidermonkey js_reporterror is the simplest jsapi function for reporting errors.

Introduction to the JavaScript shell
this is a convenient way to quickly check for syntax errors in your program without actually running it.
... werror warnings should be treated as errors.

JSErrorReport
this allows an attack by which a malicious website loads a sensitive file (say, a bank statement) cross-origin (using the user's cookies), and sniffs the generated syntax errors (via a window.onerror handler) for juicy morsels of its contents.
... to counter this attack, html5 specifies that script errors should be sanitized ("muted") when the script is not same-origin with the global for which it is loaded.

JSAPI reference
ow and catch javascript exceptions: js::createerror added in spidermonkey 38 js_isexceptionpending js_getpendingexception js_setpendingexception js_clearpendingexception js_throwstopiteration added in spidermonkey 1.8 js_isstopiteration added in spidermonkey 31 typedef jsexceptionstate js_saveexceptionstate js_restoreexceptionstate js_dropexceptionstate these functions translate errors into exceptions and vice versa: js_reportpendingexception js_errorfromexception js_throwreportederror obsolete since jsapi 29 values and types typedef jsval js::value js::value constructors: js::nullvalue added in spidermonkey 24 js::undefinedvalue added in spidermonkey 24 js::booleanvalue added in spidermonkey 24 js::truevalue added in spidermonkey 24 js::falsevalue adde...
...g obsolete since jsapi 32 jsval_to_gcthing obsolete since jsapi 32 jsval_to_private obsolete since jsapi 32 a function that behaves like typeof: js_gettypename obsolete since jsapi 34 and functions that behave like the equality operators: js_strictlyequal js_looselyequal js_samevalue memory management these functions act like the standard c malloc family of functions, except that errors are reported using the spidermonkey error apis rather than errno.

TPS Tests
for example, most errors involving bookmarks look like "places item not found in expected index", which could mean a number of issues.
... it's common for the phase after the problem to be the one reporting errors (e.g.

Animated PNG graphics
this implies that some errors may not be detected until partway through the animation.
...the purpose of this number is to detect (and optionally correct) sequence errors in an animated png, since the png specification does not impose ordering restrictions on ancillary chunks.

mozIStorageConnection
it is the primary interface for interacting with a database, including creating prepared statements, executing sql, and examining database errors.
... lasterrorstring autf8string the english error string reported by the sqlite library for the last sqlite operation.

nsIXULRuntime
logconsoleerrors boolean whether to write console errors to a log file.
... if a component encounters startup errors that might prevent the app from showing proper ui, it should set this flag to true.

XPCOM reference
this macro is meant for critical errors; like assertions, ns_errors should not be reachable.ns_if_addrefmacrons_if_releasemacrons_releasemacrons_warningmacronsgetmoduleprocthis function prototype provides the xpcom entry-point into a module.nsiabcard/thunderbird3the nsiabcard interface is used to represent and manipulate cards in the address book.
...this causes compile-time errors to occur when improper values are returned as nsresult values, thereby making it easier to catch many bugs.

Frequently Asked Questions
buildtime errors the build just broke.
... 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.

Getting Started Guide
do_queryinterface prevents xpcom type errors.
...returning an addrefed pointer in almost any form as a function result leads to several potential errors, some of which are leaks, some of which are dangling pointers.

Using nsCOMPtr
after you've been using nscomptrs for a while, and you reach unfamiliar territory, or run into compiler errors; you may want to return to this document to get help from the reference manual or the faq.
... contents status, recent changes, and plans recent changes to nscomptr getting started guide introduction using nscomptr summary reference manual the basics initialization and assignment using an nscomptr<t> as a t* efficiency and correctness compiler annoyances frequently asked questions buildtime errors runtime errors how do i...

Browser Console - Firefox Developer Tools
so it logs the same sorts of information as the web console - network requests, javascript, css, and security errors and warnings, and messages explicitly logged by javascript code.
... browser console logging the browser console logs the same sorts of messages as the web console: http requests warnings and errors (including javascript, css, security warnings and errors, and messages explicitly logged by javascript code using the console api).

DOMParser - Web APIs
doc = parser.parsefromstring(stringcontainingxmlsource, "application/xml") error handling note that if the parsing process fails, the domparser does not throw an exception, but instead returns an error document: <parsererror xmlns="http://www.mozilla.org/newlayout/xml/parsererror.xml"> (error description) <sourcetext>(a snippet of the source xml)</sourcetext> </parsererror> the parsing errors are also reported to the error console, with the document uri (see below) as the source of the error.
...@source https://gist.github.com/1129031 */ /*global document, domparser*/ (function(domparser) { "use strict"; var proto = domparser.prototype, nativeparse = proto.parsefromstring; // firefox/opera/ie throw errors on unsupported types try { // webkit returns null on unsupported types if ((new domparser()).parsefromstring("", "text/html")) { // text/html parsing is natively supported return; } } catch (ex) {} proto.parsefromstring = function(markup, type) { if (/^\s*text\/html\s*(?:;|$)/i.test(type)) { var doc = document.implementation.createhtmldocument(""); if (markup.tolowercase(...

FileError - Web APIs
best practices most people don't read the page on errors and exceptions unless they're stumped.
...in fact, many of the powerful storage apis (such as file system, blobbuilder, and filereader) throw errors if you run the app locally from file://.

FileException - Web APIs
basic concepts synchronous apis do not have error callbacks, which makes it difficult to catch errors.
...when errors occur, forward them to the main app using postmessage() as in the following: function onerror(e) { postmessage('error:' + e.tostring()); } try { //error is thrown if "log.txt" already exists.

Fullscreen API - Web APIs
event handlers the fullscreen api defines two events which can be used to detect when full-screen mode is turned on and off, as well as when errors occur during the process of changing between full-screen and windowed modes.
... events the fullscreen api defines two events which can be used to detect when full-screen mode is turned on and off, as well as when errors occur during the process of changing between full-screen and windowed modes.

HTMLObjectElement.setCustomValidity - Web APIs
syntax htmlobjectelement.setcustomvalidity(message); parameters error the message to use for validity errors.
...o!'); input.reportvalidity(); } else if (input.rangeunderflow) { input.setcustomvalidity('we need a higher number!'); input.reportvalidity(); } else if (input.rangeoverflow) { input.setcustomvalidity('thats too high!'); input.reportvalidity(); } else { input.setcustomvalidity(''); input.reportvalidity(); } } it's vital to set the message to an empty string if there are no errors.

HTMLTrackElement - Web APIs
loading 1 indicates that the text track is loading and there have been no fatal errors encountered so far.
... loaded 2 indicates that the text track has been loaded with no fatal errors.

MediaDevices.getUserMedia() - Web APIs
possible errors are: aborterror although the user and operating system both granted access to the hardware device, and no hardware issues occurred that would cause a notreadableerror, some problem occurred which prevented the device from being used.
...var constraints = { audio: true, video: { width: 1280, height: 720 } }; navigator.mediadevices.getusermedia(constraints) .then(function(mediastream) { var video = document.queryselector('video'); video.srcobject = mediastream; video.onloadedmetadata = function(e) { video.play(); }; }) .catch(function(err) { console.log(err.name + ": " + err.message); }); // always check for errors at the end.

MediaRecorder - Web APIs
mediarecorder.onerror an eventhandler called to handle the error event, including reporting errors that arise with media recording.
... these are fatal errors that stop recording.

Navigator.getUserMedia() - Web APIs
see {anch("errors")}} below for a list of the errors which can occur.
... errors examples width and height here's an example of using getusermedia(), including code to cope with various browsers' prefixes.

PaymentAddress.country - Web APIs
entifying the country in which the address is located, or an empty string if no country is available, which frequently can be assumed to mean "same country as the site owner." usage notes if the payment handler validates the address and determines that the value of country is invalid, a call to paymentrequestupdateevent.updatewith() will be made with a details object containing a shippingaddresserrors field.
... that field contains an addresserrors-compliant object whose country property is a string indicating the validation error that occurred and, if possible, suggests how to fix it.

PaymentDetailsUpdate - Web APIs
for address field specific errors, use shippingaddresserrors.
... shippingaddresserrors optional an addresserrors object which includes an error message for each property of the shipping address that could not be validated.

PaymentRequestUpdateEvent.updateWith() - Web APIs
for address field specific errors, use shippingaddresserrors.
... shippingaddresserrors optional an addresserrors object which includes an error message for each property of the shipping address that could not be validated.

PushManager.subscribe() - Web APIs
}, function(error) { // during development it often helps to log errors to the // console.
... in a production environment it might make sense to // also report information about errors back to the // application server.

PushManager - Web APIs
}, function(error) { // during development it often helps to log errors to the // console.
... in a production environment it might make sense to // also report information about errors back to the // application server.

ReadableStream.pipeThrough() - Web APIs
preventabort: if this is set to true, errors in the source readablestream will no longer abort the destination writablestream.
... preventcancel: if this is set to true, errors in the destination writablestream will no longer cancel the source readablestream.

ServiceWorkerRegistration.pushManager - Web APIs
}, function(error) { // during development it often helps to log errors to the // console.
... in a production environment it might make sense to // also report information about errors back to the // application server.

ValidityState.typeMismatch - Web APIs
the typemismatch is only one of the many possible errors and is only relevant for the email and url types.
... when the value provided doesn't match the expected value based on the type for other input types, you get different errors.

WebGLRenderingContext.getProgramInfoLog() - Web APIs
it contains errors that occurred during failed linking or validation of webglprogram objects.
... examples checking program errors var program = gl.createprogram(); // attach pre-existing shaders gl.attachshader(program, vertexshader); gl.attachshader(program, fragmentshader); gl.linkprogram(program); gl.getprograminfolog(program); specifications specification status comment webgl 1.0the definition of 'getprograminfolog' in that specification.

WebGL model view projection - Web APIs
the more operations that are done on larger numbers, the more and more errors accumulate into the result.
...this value should be kept reasonably close to the distance of the geometry in order to avoid precision errors creeping in while rendering.

Movement, orientation, and motion: A WebXR example - Web APIs
logging errors a function called logglerror() is implemented to provide an easily customized way to output logging information for errors that occur while executing webgl functions.
... function logglerror(where) { let err = gl.geterror(); if (err) { console.error(`webgl error returned by ${where}: ${err}`); } } this takes as its only input a string, where, which is used to indicate what part of the program generated the error, since similar errors can have in multiple situations.

Web APIs
a angle_instanced_arrays abortcontroller abortsignal absoluteorientationsensor abstractrange abstractworker accelerometer addresserrors aescbcparams aesctrparams aesgcmparams aeskeygenparams ambientlightsensor analysernode animation animationeffect animationevent animationplaybackevent animationtimeline arraybufferview attr audiobuffer audiobuffersourcenode audioconfiguration audiocontext audiocontextlatencycategory audiocontextoptions audiodestinationnode audiolistener audionode audionodeoptions audioparam audioparamdescri...
...dex_uint oes_fbo_render_mipmap oes_standard_derivatives oes_texture_float oes_texture_float_linear oes_texture_half_float oes_texture_half_float_linear oes_vertex_array_object ovr_multiview2 offlineaudiocompletionevent offlineaudiocontext offscreencanvas orientationsensor oscillatornode overconstrainederror p pagetransitionevent paintworklet pannernode parentnode passwordcredential path2d payererrors paymentaddress paymentcurrencyamount paymentdetailsbase paymentdetailsupdate paymentitem paymentmethodchangeevent paymentrequest paymentrequestevent paymentrequestupdateevent paymentresponse paymentvalidationerrors pbkdf2params performance performanceentry performanceeventtiming performanceframetiming performancelongtasktiming performancemark performancemeasure performancenavigation per...

Understandable - Accessibility
data is checked for errors, and the user is given an opportunity to correct them.
... checking data — as covered in 3.3.1, a combination of client-side and server-side validation should be used to detect errors and display helpful messages to the user to allow them to correct their inputs.

Using HTML sections and outlines - Developer guides
</script> <![endif]--> <noscript> <p><strong>this web page requires javascript to be enabled.</strong></p> <p>javascript is an object-oriented computer programming language commonly used to create interactive effects within web browsers.</p> <p><a href="https://goo.gl/koeeaj">how to enable javascript?</a></p> </noscript> note: this code will also cause the html validator to return errors.
... this isn't a really bad thing neccessarily — sites will often have a few validation errors — but it's something to be aware of still.

<img>: The Image Embed element - HTML: Hypertext Markup Language
alt text is also displayed on the page if the image can't be loaded for some reason: for example, network errors, content blocking, or linkrot.
... image loading errors if an error occurs while loading or rendering an image, and an onerror event handler has been set on the error event, that event handler will get called.

<u>: The Unarticulated Annotation (Underline) element - HTML: Hypertext Markup Language
use cases valid use cases for the <u> element include annotating spelling errors, applying a proper name mark to denote proper names in chinese text, and other forms of annotation.
...this is a common styling for spelling errors.

Global attributes - HTML: Hypertext Markup Language
spellcheck an enumerated attribute defines whether the element may be checked for spelling errors.
... it may have the following values: true, which indicates that the element should be, if possible, checked for spelling errors; false, which indicates that the element should not be checked for spelling errors.

HTTP response status codes - HTTP
responses are grouped in five classes: informational responses (100–199), successful responses (200–299), redirects (300–399), client errors (400–499), and server errors (500–599).
... 422 unprocessable entity (webdav) the request was well-formed but was unable to be followed due to semantic errors.

Error - JavaScript
error objects are thrown when runtime errors occur.
... description runtime errors result in new error objects being created and thrown.

Promise.any() - JavaScript
if no promises in the iterable fulfil (if all of the given promises are rejected), then the returned promise is rejected with an aggregateerror, a new subclass of error that groups together individual errors.
... rejection if all of the passed-in promises reject, promise.any asynchronously rejects with an aggregateerror object, which extends error, and contains an errors property with an array of rejection values.

Promise.prototype.catch() - JavaScript
og('not fired due to the catch'); }); // the following behaves the same as above p1.then(function(value) { console.log(value); // "success!" return promise.reject('oh, no!'); }).catch(function(e) { console.error(e); // "oh, no!" }).then(function(){ console.log('after a catch the chain is restored'); }, function () { console.log('not fired due to the catch'); }); gotchas when throwing errors // throwing an error will call the catch method most of the time var p1 = new promise(function(resolve, reject) { throw new error('uh-oh!'); }); p1.catch(function(e) { console.error(e); // "uh-oh!" }); // errors thrown inside asynchronous functions will act like uncaught errors var p2 = new promise(function(resolve, reject) { settimeout(function() { throw new error('uncaught exceptio...
...n!'); }, 1000); }); p2.catch(function(e) { console.error(e); // this is never called }); // errors thrown after resolve is called will be silenced var p3 = new promise(function(resolve, reject) { resolve(); throw new error('silenced exception!'); }); p3.catch(function(e) { console.error(e); // this is never called }); if it is resolved //create a promise which would not call onreject var p1 = promise.resolve("calling next"); var p2 = p1.catch(function (reason) { //this is never called console.error("catch p1!"); console.error(reason); }); p2.then(function (value) { console.log("next promise's onfulfilled"); /* next promise's onfulfilled */ console.log(value); /* calling next */ }, function (reason) { console.log("next promise's onrejected"); console.

let - JavaScript
} you may encounter errors in switch statements because there is only one block.
... break; } however, it's important to point out that a block nested inside a case clause will create a new block scoped lexical environment, which will not produce the redeclaration errors shown above.

try...catch - JavaScript
try { throw 'myexception'; // generates an exception } catch (e) { // statements to handle any exceptions logmyerrors(e); // pass exception object to error handler } the catch-block specifies an identifier (e in the example above) that holds the value of the exception; this value is only available in the scope of the catch-block.
...myroutine(); // may throw three types of exceptions } catch (e) { if (e instanceof typeerror) { // statements to handle typeerror exceptions } else if (e instanceof rangeerror) { // statements to handle rangeerror exceptions } else if (e instanceof evalerror) { // statements to handle evalerror exceptions } else { // statements to handle any unspecified exceptions logmyerrors(e); // pass exception object to error handler } } a common use case for this is to only catch (and silence) a small subset of expected errors, and then re-throw the error in other cases: try { myroutine(); } catch (e) { if (e instanceof rangeerror) { // statements to handle this very common expected error } else { throw e; // re-throw the error unchanged } } the exception ...

Progressive web app structure - Progressive web apps (PWAs)
progressive: start with the "good, old basic website” and progressively add new features while remembering to detect if they are available in the browser and gracefully handle any errors that crop up if support is not available.
...it provides fine-grained control — the stream can be started, chained with another stream, cancelled, checked for errors, and more.

Structural overview of progressive web apps - Progressive web apps (PWAs)
progressive: start with the "good, old basic website” and progressively add new features while remembering to detect if they are available in the browser and gracefully handle any errors that crop up if support is not available.
...it provides fine-grained control: the stream can be started, chained with another stream, canceled, checked for errors, and more.

Same-origin policy - Web security
failure to do this may result in permission errors.
...error details for syntax errors are only available for same-origin scripts.

SDK API Lifecycle - Archive of obsolete content
the amo validator will throw errors when deprecated modules are used, and these add-ons will therefore fail amo review.

console - Archive of obsolete content
the console defines a number of logging levels, from "more verbose" to "less verbose", and a number of different logging functions that correspond to these levels, which are arranged in order of "severity" from informational messages, through warnings, to errors.

jpm - Archive of obsolete content
after fixing the validation errors, you can run the command again.

Troubleshooting - Archive of obsolete content
check your text console when errors are generated in the sdk's apis and your code, they are logged to the text console.

Downloading Files - Archive of obsolete content
xt, passwordrealm, savepassword, pwd) { pwd.value = hardcodedpassword; return true; }, promptusernameandpassword: function(dialogtitle, text, passwordrealm, savepassword, user, pwd) { user.value = hardcodedusername; pwd.value = hardcodedpassword; return true; } }; persist.saveuri(urltosave, null, null, null, "", nsfileinstance, privacy); the above is going to give you errors about missing nsidownloadprogresslistener methods, so you should implement that as well.

Preferences - Archive of obsolete content
la.org/preferences-service;1"] .getservice(components.interfaces.nsiprefservice); prefservice.savepreffile(null); checking for existence of a key if you try to get the value of a nonexistent preference, an error will be thrown: error: ns_error_unexpected: component returned failure code: 0x8000ffff (ns_error_unexpected) [nsiprefbranch.getcharpref] to avoid such errors, you should check whether the key exists or not using nsiprefservice.getpreftype(), as shown below: var prefservicebranch = components.classes["@mozilla.org/preferences-service;1"] .getservice(components.interfaces.nsiprefservice).getbranch(""); if(prefservicebranch.getpreftype('extensions.myext.key')){ //key exist!

xml:base support in old browsers - Archive of obsolete content
note however, that this code is not based on a thorough examination of the specs related to forming base uris and could well have a number of errors.

Creating custom Firefox extensions with the Mozilla build system - Archive of obsolete content
otherwise the first module's xpt file will be overwritten by the second and you'll get ns_error_xpc_bad_iid errors when you try to access its idl interfaces from your code.

How to convert an overlay extension to restartless - Archive of obsolete content
errors can erratically happen on next load of the same file in certain instances.

Migrating from Internal Linkage to Frozen Linkage - Archive of obsolete content
for errors about undeclared do_createinstance: #include "nscomponentmanagerutils.h" for errors about undeclared do_getservice: #include "nsservicemanagerutils.h" for errors about undeclared ns_getspecialdirectory: #include "nsdirectoryserviceutils.h" utility classes some utility classes could previously be created with ns_new* utility functions.

Chapter 3: Introduction to XUL—How to build a more intuitive UI - Archive of obsolete content
if you are embedding a script in a page, you should bracket your code inside a cdata section as shown in listing 18; this will avoid errors caused by mistakenly reading "&" and other characters as the beginnings of entity references.

Adding Toolbars and Toolbar Buttons - Archive of obsolete content
if you put the toolbarpalette element inside the window element in your overlay, some weird errors will begin to happen.

Appendix E: DOM Building and Insertion (HTML & XUL) - Archive of obsolete content
for security reasons, and to prevent errors, care needs to be taken to avoid evaluating arbitrary text as html.

Handling Preferences - Archive of obsolete content
if you are going to use xpcom, you should always set a default value to your preferences, or use a try / catch block to prevent unhandled errors.

Local Storage - Archive of obsolete content
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.

Setting up an extension development environment - Archive of obsolete content
logs errors in chrome files to the error console.

An Interview With Douglas Bowman of Wired News - Archive of obsolete content
fortunately, our chief engineer was able to write some code that scraped through the database looking for errors like this which would invalidate our markup.

cert_override.txt - Archive of obsolete content
43 for https (ssl) hash algorithm oid sha1-256: oid.2.16.840.1.101.3.4.2.1 (most used) sha-384: oid.2.16.840.1.101.3.4.2.2 sha-512: oid.2.16.840.1.101.3.4.2.3 certificate fingerprint using previous hash algorithm one or more characters for override type: m : allow mismatches in the hostname u : allow untrusted certs (whether it's self signed cert or a missing or invalid issuer cert) t : allow errors in the validity time, for example, for expired or not yet valid certs certificate's serial number and the issuer name as a base64 encoded string ...

No Proxy For configuration - Archive of obsolete content
all proxied urls will return errors, all non-proxied connections will be attempted normally (direct connection).

Locked config settings - Archive of obsolete content
if you suspect syntax errors in your config file, you can display the exact error message by enclosing your code in a try-catch block: try { ...

Compiling The npruntime Sample Plugin in Visual Studio - Archive of obsolete content
in fact, all win32 api functions dealing with character strings can be added an 'a' to the end to avoid unicode cast errors.

Dehydra Function Reference - Archive of obsolete content
strict boolean: controls js strict mode werror boolean: turns js warnings into errors gczeal int: this is a write-only parameter to set turn on frequent garbage collection.

JSS build instructions for OSX 10.6 - Archive of obsolete content
/secu...using_jss.html steps: export all this: build_opt="1" cvsroot=":pserver:anonymous@cvs-mirror.mozilla.org:/cvsroot" java_home=$(/usr/libexec/java_home") no_mdupdate="1" nsdistmode="copy" ns_use_gcc="1" create working dir: mkdir nss-jss cd nss-jss obtain source: altought manual said nspr_4_6_4_rtm, nss_3_11_4_rtm, jss_4_2_5_rtm, they didnt work for osx, giving many compiling errors.

JavaScript Client API - Archive of obsolete content
ncengine.call(this, "foo"); } fooengine.prototype = { __proto__: weave.syncengine.prototype, _recordobj: foorecord, _storeobj: foostore, _trackerobj: footracker }; as you can see, there isn't actually any new code here at all; the prototype simply defines some metadata such as the store and tracker classes to use, and the human-readable name that will be used in the log files to identify errors and status messages coming from this engine.

Creating a Help Content Pack - Archive of obsolete content
understanding the syntax is important because small syntax errors can mean that a whole file won't be loaded correctly.

Helper Apps (and a bit of Save As) - Archive of obsolete content
if any read or write errors occur, abort the whole process: cancel the channel.

JavaScript crypto - Archive of obsolete content
example of cryptomechanismflags and cipherflags pkcs11mechanismflags = pkcs11_mech_dsa_flag | pkcs11_mech_skipjack_flag | pkcs11_mech_random_flag; pkcs11cipherflags = 0; return values js_ok_add_module = 3 // successfully added a module js_err_other = -1 // errors other than the following js_err_user_cancel_action = -2 // user aborted an action js_err_incorrect_num_of_arguments = -3 // calling a method w/ incorrect # of // arguments js_err_add_module = -5 // error adding a module js_err_bad_module_name = -6 // the module name is invalid js_err_add_module_duplicate = -10 //...

New Security Model for Web Services - Archive of obsolete content
reports errors (validation, wellformedness, file not found, etc.) to the console via nsiconsoleservice.

Standalone XPCOM - Archive of obsolete content
link errors when building xpcom standalone this is usually due to xpcom not being built standalone.

Abc Assembler Tests - Archive of obsolete content
the abcasm/abs_helper.as file which defines the following functions: start(summary:string):void - start a new test section described by 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.

Tamarin build documentation - Archive of obsolete content
alternatively, run make, in which case the process will complete with errors when it tries to create the shared lib crt0.o: $ /android-public/android-ndk/toolchains/arm-eabi-4.4.0/prebuilt/darwin-x86/bin/../lib/gcc/arm-eabi/4.4.0/../../../../arm-eabi/bin/ld: crt0.o: no such file: no such file or directory collect2: ld returned 1 exit status make[2]: *** [link_app.] error 1 make[1]: *** [openssl] error 2 make: *** [build_apps] error 1 you can ignore these errors.

Tamarin Build System Documentation - Archive of obsolete content
the compile phase compiles all of the tamarin source code and builds all of the shell executables, any errors will stop the phase and a red box will appear on the slave where the error occurred.

Tamarin-central rev 703:2cee46be9ce0 - Archive of obsolete content
flash10576k tc-700740k tc-703655k known issues known failures in the acceptance testsuite include: number failures in testsuite when running on linux windows mobile system.privatebytes and -memstats privatebytes always returns 0 amd64 longjmp hack needs reengineering on non-windows platforms different runtime errors when -dforcemir set in acceptance test run arm: math failures running with thumb or arm jit and interp.

URIs and URLs - Archive of obsolete content
also to be somewhat tolerant to syntax errors the parser has to know more about the specific syntax of the urls for that scheme.

Venkman Internals - Archive of obsolete content
these notes are written by such readers: as you learn please correct any errors.

Venkman Introduction - Archive of obsolete content
you can also use commands available in the debug menu and from the console to stop at errors or at exceptions.

Using Breakpoints in Venkman - Archive of obsolete content
one of the most important aspects of debugging a script or software program is the ability to examine variables—function return values, errors, counters, variable scopes—as they change over the course of the script execution.

Using XPInstall to Install Plugins - Archive of obsolete content
caveat: because of possible administrator issues, handle errors carefully!

addDirectory - Archive of obsolete content
in some situations, adddirectory may return other errors.

getLastError - Archive of obsolete content
the getlasterror method does not return errors from methods that return objects, such as getfolder.

performInstall - Archive of obsolete content
in some situations the method may return other errors.

registerChrome - Archive of obsolete content
in some situations the method may return other errors.

Learn XPI Installer Scripting by Example - Archive of obsolete content
recall that an install process takes the following general form: initinstall(); if (verify_space()) { err = add_dirs_and_files; register_files; if (err==success) { performinstall() }; else { cancelinstall() }; } in this arrangement, the actual execution of the installation is checked against the errors returned from the addition of files to the installation, which may itself have been conditioned on some verification of version and necessary disk space.

IO - Archive of obsolete content
file errors see file errors for a list of errors that might occur while using files.

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.

SeaMonkey - making custom toolbar (SM ver. 1.x) - Archive of obsolete content
copy and paste the line from here, to avoid typing errors: content,install,url,resource:/chrome/custombutton/ explanation: this line registers your custom toolbar button extension, linking it into seamonkey.

Custom toolbar button - Archive of obsolete content
copy the name from here and paste it, to avoid typing errors: custom-toolbar-button@example.com perform the following steps in this new directory, creating two files and a directory there.

Localization - Archive of obsolete content
otherwise, errors will occur as it won't be able to find the entities.

XULRunner tips - Archive of obsolete content
closewhendone", true); pref("browser.download.manager.opendelay", 0); pref("browser.download.manager.focuswhenstarting", false); pref("browser.download.manager.flashcount", 2); // pref("alerts.slideincrement", 1); pref("alerts.slideincrementtime", 10); pref("alerts.totalopentime", 4000); pref("alerts.height", 50); if you are missing preferences that a dialog requires, you will get the following errors: component returned failure code: 0x8000ffff (ns_error_unexpected) [nsiprefbranch.getboolpref] error: dialog has no properties source file: chrome://mozapps/content/downloads/u...ontenttype.xul line: 1 enabling password manager these preferences seem to be the default in firefox, however, they are missing in xulrunner.

XUL Explorer - Archive of obsolete content
indicator in the statusbar shows errors.

reftest opportunities files - Archive of obsolete content
many of these were checked with the layout regression test tool, which has been described as difficult to use and it apparently reported a lot of regressions that were not errors.

2006-11-17 - Archive of obsolete content
however he has been unsuccessful and gets the following errors: checking for gtk - version >= 1.2.0...

2006-11-24 - Archive of obsolete content
however he has been unsuccessful and a bunch of errors.

Extentsions FAQ - Archive of obsolete content
read http://developer.mozilla.org/en/docs/extension_faq and check if there are any errors in js console.

2006-09-29 - Archive of obsolete content
when he runs xulrunner from the command line, it fails silently without any errors.

NPN_Write - Archive of obsolete content
note: you should actually handle errors, which this example doesn't do.

Adobe Flash - Archive of obsolete content
handle errors (no flash installed, etc.) example 1 uses the regexp (regular expression) object exposed to javascript strings.

SAX - Archive of obsolete content
nsisaxerrorhandler receive notification of errors in the input stream.

Threats - Archive of obsolete content
many threats against data and resources are possible because of mistakes—either bugs in operating system and applications that create exploitable vulnerabilities, or errors made by end users and administrators.

Building a Theme - Archive of obsolete content
if you get a message that the install.rdf is malformed, it is helpful to load it into firefox using the file->open file command and it will report xml errors to you.

Developing cross-browser and cross-platform pages - Archive of obsolete content
as a web author, you understandably want to avoid script errors and page layout problems and you may want to ensure your scripts reach as wide an audience as possible.

Browser Detection and Cross Browser Support - Archive of obsolete content
try { // code to implement fancy menu } catch (errors) { // handle exceptions } </script> <noscript> <!-- if javascript is not enabled, then the browser will display the contents of the noscript tag which in this case is a simple menu implemented as an unordered list.

New in JavaScript 1.5 - Archive of obsolete content
changed functionality in javascript 1.5 runtime errors are now reported as exceptions.

Object.prototype.__noSuchMethod__ - Archive of obsolete content
if this method cannot be called, either as if undefined by default, if deleted, or if manually set to a non-function, the javascript engine will revert to throwing typeerrors.

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.

Styling the Amazing Netscape Fish Cam Page - Archive of obsolete content
i did it that way because it's a lot less likely to trigger a situation where rounding errors force the two floats to total more than 100% the width of the parent, as could happen if the floats' element boxes were made to total 50%.

forEach - Archive of obsolete content
a much more sane approach would be to count on the implementation to throw errors if wrong arguments are provided and implement this in fewer lines of code.

XForms Repeat Element - Archive of obsolete content
there are a number of errors that may occur, especially when these attributes are used with html:table.

The Business Benefits of Web Standards - Archive of obsolete content
using validation tools such as the w3c validator helps by spotting coding errors and making sure html code is well-formed, which eliminates ambiguity in parsing by browsers.

XUL Parser in Python - Archive of obsolete content
i have probably made some errors and undoubtedly written some strange, graceless python.

404 - MDN Web Docs Glossary: Definitions of Web-related terms
learn more list of http response codes advice for beginners on avoiding 404 errors ...

Exception - MDN Web Docs Glossary: Definitions of Web-related terms
in javascript syntax errors are a very common source of exceptions.

Syntax - MDN Web Docs Glossary: Definitions of Web-related terms
even small errors, like a missing parenthesis, can stop source code from compiling successfully.

Validator - MDN Web Docs Glossary: Definitions of Web-related terms
a validator is a program that checks for syntax errors in code.

HTML: A good basis for accessibility - Learn web development
these values cause unexpected behavior when copying or dragging links, opening links in a new tab or window, bookmarking, and when javascript is still downloading, errors out, or is disabled.

HTML: A good basis for accessibility - Learn web development
these values cause unexpected behavior when copying or dragging links, opening links in a new tab or window, bookmarking, and when javascript is still downloading, errors out, or is disabled.

Fundamental CSS comprehension - Learn web development
there are two errors in the provided rulesets.

How CSS is structured - Learn web development
for example, these declarations are valid css: margin: 0 auto; padding-left: 10px; but these declarations are invalid: margin: 0auto; padding- left: 10px; do you see the spacing errors?

HTML basics - Learn web development
failing to add a closing tag is one of the standard beginner errors and can lead to strange results.

Tips for authoring fast-loading HTML pages - Learn web development
for example, html tidy can remove whitespace and optional ending tags; however, it will refuse to run on a page with serious markup errors.

Getting started with HTML - Learn web development
it will cause errors or unexpected behavior, as you can see in the live example below.

What’s in the head? Metadata in HTML - Learn web development
this is useful as it makes sure that the html is all loaded before the javascript runs, so that you don't get errors resulting from javascript trying to access an html element that doesn't exist on the page yet.

HTML table advanced features and accessibility - Learn web development
</tbody> note: this method creates very precise associations between headers and data cells but it uses a lot more markup and does not leave any room for errors.

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.

Introducing asynchronous JavaScript - Learn web development
error handling is much better — all errors are handled by a single .catch() block at the end of the block, rather than being individually handled in each level of the "pyramid".

Function return values - Learn web development
this way, your program will be less likely to throw errors.

Fetching data from the server - Learn web development
to handle errors, we chain a .catch() block onto the end of the chain.

Third-party APIs - Learn web development
the second function works nearly exactly the same way in reverse, but we also have to take the extra step of checking that pagenumber is not already zero before decrementing it — if the fetch request runs with a minus page url parameter, it could cause errors.

Basic math in JavaScript — numbers and operators - Learn web development
the strict versions tend to result in fewer errors, so we recommend you use them.

Handling text — strings in JavaScript - Learn web development
if your program is raising such errors, then go back and check all your strings to make sure you have no missing quote marks.

Test your skills: variables - Learn web development
variables 3 the final task for now — in this case you are provided with some existing code, which has two errors present in it.

What is JavaScript? - Learn web development
if the javascript loads and tries to run before the html and css it is affecting has been loaded, errors can occur.

JavaScript First Steps - Learn web development
never fear — this article aims to save you from tearing your hair out over such problems by providing you with some simple tips on how to find and fix errors in javascript programs.

Inheritance in JavaScript - Learn web development
without using this convention, we would get errors every time we called get or set.

Working with JSON - Learn web development
you should be careful to validate any data you are attempting to use (although computer-generated json is less likely to include errors, as long as the generator program is working correctly).

Object building practice - Learn web development
the following will do this job — add it to the bottom of your code now: let balls = []; while (balls.length < 25) { let size = random(10,20); let ball = new ball( // ball position always drawn at least one ball width // away from the edge of the canvas, to avoid drawing errors random(0 + size,width - size), random(0 + size,height - size), random(-7,7), random(-7,7), 'rgb(' + random(0,255) + ',' + random(0,255) + ',' + random(0,255) +')', size ); balls.push(ball); } the while loop creates a new instance of our ball() using random values generated with our random() function, then push()es it onto the end of our balls array, but only while...

Properly configuring server MIME types - Learn web development
this has sheltered many web administrators from their own errors, since internet explorer will continue to process content as expected even though the web server is misconfigured, e.g.

Website security - Learn web development
sql injection types include error-based sql injection, sql injection based on boolean errors, and time-based sql injection.

Ember interactivity: Events, classes and state - Learn web development
replace it with the following: this.todos.add(text); if we try this out in the todo app in our browser (npm start, go to localhost:4200), it will look like nothing happens after hitting the enter key (although the fact that the app builds without any errors is a good sign).

Routing in Ember - Learn web development
it also tells ember how to interact with your route, such as when loading arbitrary data, handling errors while loading that data, or interpreting dynamic segments of the url.

Framework main features - Learn web development
we could write our own javascript that raises these errors for us, but it would make our source code significantly more verbose.

Componentizing our Svelte app - Learn web development
we will just declare the onclick prop assigning a dummy handler to prevent errors, like this: export let onclick = (clicked) => {} and we'll declare the following reactive statement — $: onclick(filter) — to call the onclick handler whenever the filter variable is updated.

Creating our first Vue component - Learn web development
this would result in errors with assistive technology since the id is needed to correctly map labels to their checkboxes.

Accessibility information for UI designers and developers
this is specifically important in these cases: the user input is about legal commitments or financial transactions it updates or removes the user's data in a system when recording tests responses in those cases, ensure users can change submissions, automatically check for errors.

Building SpiderMonkey with UBSan
(for automated testing outside of gdb, you can instead build with -fsanitize=undefined-trap -fsanitize-undefined-trap-on-error, but then you lose ubsan's diagnostics and the ability to continue past errors.) known bugs.

Command line options
other options need to be documented -print-xpcom-dir -print-xpcom-dirlist -kill -killall -f -ftimeout -fwait -unsetdefaultmail gtk options -no-deelevate (running windows as administrator with launcher process enabled causes drag and drop errors - how to fix) references chrome: command line test documentation for command-line features (mozilla.org) toolkit/xre/nsapprunner.cpp browser/components/nsbrowsercontenthandler.js suite/browser/nsbrowsercontenthandler.js mail/components/nsmaildefaulthandler.js installer command line options original document information author(s): ben goodger, steffen wilberg, seth spitzer, daniel...

Debugging OpenGL
this is generally only useful in cases where you know that no error should occur, since there are cases where perfectly valid webgl code may generate opengl errors.

Debugging on Mac OS X
select "build" from the left of the scheme editor window, and check that there is nothing listed under targets (otherwise it may cause problems when you try to run the executable for debugging since you will get build errors).

Simple Instantbird build
on linux, this can manifest as problems setting up the virtualenv for running tests (failure to install pip or virtualenv because of os access denied errors, where access is denied not because of permission problems, but because the paths being accessed have been truncated, and so do not exist).

Simple SeaMonkey build
minimum and recommended hardware requirements for mozilla development are: recommended: 8gb of ram (having only 4gb ram and 4gb swap may give memory errors during compile) 35 gb free disk space.

Eclipse CDT Manual Setup
you should be able to use the list of unresolved includes to help figure out what the problem is (see also the parser errors section for more troubleshooting tips).

Gecko Logging
the log crate lists the available log levels: log level purpose rust logging levels error designates very serious errors.

Obsolete Build Caveats and Tips
warning: due to a bug in old versions of mozillabuild (prior to 1.6), if you download version 7.1 of the windows 7 sdk (which is the current version available), your build will fail, often while building cairo with "ocidl.h" errors.

Listening to events on all tabs
note: astatus may be a success code even for server generated errors, such as the http 404 file not found error.

How to investigate Disconnect failures
the event viewer can be found on windows: computer management > event viewer > windows logs > application and here we look for errors that overlapped with the test run; we cannot see the freezes (the main thread is blocked).

Creating a New Protocol
building the new protocol to build the new protocol declaration and generate headers, make in ipc/ipdl: make -c objdir/ipc/ipdl if there are any protocol-level errors, the ipdl compiler will print the relevant error messages and stop.

IPDL Tutorial
normal errors should be signaled with a message or return value.

AddonManager
addoninstall errors constant description error_network_failure a network error occurred.

AsyncShutdown.jsm
used for providing more details when logging errors or crashing.

Downloads.jsm
examples downloading to a local file this example downloads an html file without showing progress, handling errors programmatically.

FxAccountsProfileClient.jsm
examples using the fxaccountsprofileclient chrome code let client = new fxaccountsprofileclient({ serverurl: "https://profile.accounts.firefox.com/v1", token: "fxa_oauth_bearer_token", }); client.fetchprofile().then(profile => console.log(profile)); error handling the fxaccountsprofileclient.jsm normalizes request and client errors into fxaccountsprofileclienterror object.

JavaScript OS
os.constants os-related constants, including errors, file opening modes, system configuration, etc.

OS.File.Error
instances of os.file.error are used by os.file to notify of file-related errors.

OSFile.jsm
shared components os.path and os.constants.path manipulation of paths os.file.error representation of file-related errors os.file.info representation of file information (size, creation date, etc.) os.file.directoryiterator.entry file information obtained while visiting a directory ...

Bootstrapping a new locale
if you just checked out the localizable parts of en-us above, it will create a plethora of warnings no such file or directory, but no errors.

L10n Checks
k only for missing and obsolete entities and files, by setting the -t parameter, e.g.: check-l10n-completeness -t suite/locales/l10n.ini ../l10n/ de check access keys in all modes you can tell l10n checks to check if the access keys are set properly, by setting the -a parameter, e.g.: check-l10n-completeness -a 1 suite/locales/l10n.ini ../l10n/ de there are three modes available: 1: show just errors 2: show errors and important warnings 3: show all errors and warnings spell checking in all modes you can tell l10n checks to search for spelling errors, by setting the -c parameter, e.g.: check-l10n-completeness -c suite/locales/l10n.ini ../l10n/ de spell checking requires enchant and pyenchant to be installed on the system.

Localizing XLIFF files for iOS
open the file in firefox to have it run a validity check and correct any errors it might yell about.

Localizing with Koala
this will allow you to track changes, export them to remote repositories (first on bitbucket, later on hg.mozilla.org) and revert files to earlier versions in case of errors.

Localizing with Mozilla Translator
after translating those strings (if using the edit phrase dialog, you can get translation suggestions for strings having an original text equal to existing translations), you can run some automated tests to detect typical errors.

SVN for Localizers
keep this in mind because if you did a lot of work and you made some errors in just one file, maybe it would be wiser to simply correct those errors instead of reverting your working directory and losing all your work.

Localization technical reviews
compare-locale we run the compare-locales tool on the new locale to get the statistics on translation of strings and report basic errors.

MathML Demo: <mtable> - tables and matrices
ab ab ab ab ab ab , modulo pixel roundoff errors.

Mozilla DOM Hacking Guide
user's guide to class info warning: this document has not yet been reviewed by the dom gurus, it might contain some errors.

Mozilla Web Developer FAQ
css parsing errors are reported to the javascript console.

Mozilla Web Services Security Model
any errors in xml syntax, as well as many failures to follow the format, will cause the document to be ignored.

Preference reference
javascript.options.showinconsolethe preference javascript.options.showinconsole controls whether errors or warnings in chrome code are shown in the error console.javascript.options.stricttechnical review completed.mail.tabs.drawintitlebarstarting in thunderbird 17.0, the tabs are drawn in the title bar.

Profile Manager
if you attempt to perform any operation on a locked profile, you'll get a warning; if you choose to continue despite the warning, you may encounter errors or corrupt a profile.

AsyncTestUtils extended framework
if you aren't using logsploder, then this just makes your tests fail if errors get logged to the error console (like you see if you go to the "tools | error console" menu).

NSPR Error Handling
this chapter describes the functions for retrieving and setting errors and the error codes set by nspr.

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!

PR_ConnectContinue
- other errors: the nonblocking connect has failed with this error code.

PR_GetConnectStatus
if pr_geterror returns pr_in_progress_error, the nonblocking connection is still in progress and has not completed yet.other errors indicate that the connection has failed.

NSS_3.12.2_release_notes.html
new in nss 3.12.2 new functions in the nss shared library: sec_pkcs12addcertorchainandkey (see p12.h) new pkcs11 errors (see secerr.h) sec_error_pkcs11_general_error sec_error_pkcs11_function_failed sec_error_pkcs11_device_error bugs fixed the following bugs have been fixed in nss 3.12.2.

NSS_3.12_release_notes.html
ug for libpkix cert validation failures discovered from running vfyserv bug 390499: libpkix does not check cached cert chain for revocation bug 390502: libpkix fails cert validation when no valid crl (nist validation policy is always enforced) bug 390530: libpkix does not support time override bug 390536: cert validation functions must validate leaf cert themselves bug 390554: all pkix_nullcheck_ errors are reported as pkix alloc error bug 390888: cert_verify* functions should be able to use libpkix bug 391457: libpkix does not check for object ref leak at shutdown bug 391774: pkix_shutdown is not called by nssinit.c bug 393174: memory leaks in ocspclnt/pkix.

NSS 3.18.1 release notes
but when firefox 38 went into beta, there was a huge spike in the number of certificate verification errors attributed to this change.

NSS 3.19.2.4 release notes
security fixes in nss 3.19.2.4 the following security fixes from nss 3.21 have been backported to nss 3.19.2.4: bug 1185033 / cve-2016-1979 - use-after-free during processing of der encoded keys in nss bug 1209546 / cve-2016-1978 - use-after-free in nss during ssl connections in low memory bug 1190248 / cve-2016-1938 - errors in mp_div and mp_exptmod cryptographic functions in nss compatibility nss 3.19.2.4 shared libraries are backward compatible with all older nss 3.x shared libraries.

NSS 3.21 release notes
has been selected ssl_preinfo_cipher_suite - used with sslpreliminarychannelinfo to indicate that a tls cipher suite has been selected ssl_preinfo_all - used with sslpreliminarychannelinfo to indicate that all preliminary information has been set notable changes in nss 3.21 nss now builds with elliptic curve ciphers enabled by default (bug 1205688) nss now builds with warnings as errors (bug 1182667) the following ca certificates were removed cn = verisign class 4 public primary certification authority - g3 sha1 fingerprint: c8:ec:8c:87:92:69:cb:4b:ab:39:e9:8d:7e:57:67:f3:14:95:73:9d cn = utn-userfirst-network applications sha1 fingerprint: 5d:98:9c:db:15:96:11:36:51:65:64:1b:56:0f:db:ea:2a:c2:3e:f1 cn = tc trustcenter universal...

NSS 3.45 release notes
hat might have copied the unit test code verbatim bug 1550022 - ensure nssutil3 gets built on android bug 1528174 - chacha20poly1305 should no longer modify output length on failure bug 1549382 - don't leak in pkcs#11 modules if c_getslotinfo() returns error bug 1551041 - fix builds using gcc < 4.3 on big-endian architectures bug 1554659 - add versioning to openbsd builds to fix link time errors using nss bug 1553443 - send session ticket only after handshake is marked as finished bug 1550708 - fix gyp scripts on solaris sparc so that libfreebl_64fpu_3.so builds bug 1554336 - optimize away unneeded loop in mpi.c bug 1559906 - fipstest: use ckm_tls12_master_key_derive instead of vendor specific mechanism bug 1558126 - tls_aes_256_gcm_sha384 should be marked as fips compatible bug ...

NSS 3.46 release notes
bugs fixed in nss 3.46 bug 1572164 - don't unnecessarily free session in nsc_wrapkey bug 1574220 - improve controls after errors in tstcln, selfserv and vfyserv cmds bug 1550636 - upgrade sqlite in nss to a 2019 version bug 1572593 - reset advertised extensions in ssl_constructextensions bug 1415118 - nss build with ./build.sh --enable-libpkix fails bug 1539788 - add length checks for cryptographic primitives (cve-2019-17006) bug 1542077 - mp_set_ulong and mp_set_int should return errors on bad values bug 1572791 - r...

NSS sources building testing
if you get name resolution errors, try to disable ipv6 on the loopback device.

NSPR functions
pr_cleanup error reporting nss uses nspr's thread-specific error code to report errors.

NSS Tools certutil-tasks
most certutil errors provide no detail.

Tutorial: Embedding Rhino
evaluation of the script looks up variables in scope, and errors will be reported with the filename <cmd> and line number 1.

Scripting Java
one thing to be careful of is rhino's handling of errors in specifying java package or class names.

SpiderMonkey Build Documentation
n installed to c:/mozilla-build/msys/local: /bin/sh ../configure.in --with-nspr-cflags="-ic:/mozilla-build/msys/local/include" \ --with-nspr-libs="c:/mozilla-build/msys/local/lib/libnspr4.a \ c:/mozilla-build/msys/local/lib/libplds4.a \ c:/mozilla-build/msys/local/lib/libplc4.a" if you get symbol loading or dynamic library errors, you can force the correct nspr to load with: path="$path;c:/mozilla-build/msys/local/lib/" ./js specifying installation directories make install puts files in the following directories by default.

Hacking Tips
break on valgrind errors sometimes, a bug can be reproduced under valgrind but hardly under gdb.

Exact Stack Rooting
rootedobject obj(cx, js_newobject(cx, clasp, nullptr(), nullptr()); common pitfalls the c++ type system allows us to eliminate the possibility of most common errors; however, there are still a few things that you can get wrong that the compiler cannot help you with.

SpiderMonkey Internals
in general, both functions inside spidermonkey and jsapi callback functions signal errors by calling js_reporterror or one of its variants, or js_setpendingexception, and returning js_false or null.

JSAPI Cookbook
actually outputting errors.

JSObjectOps.getRequiredSlot
these operations are infallible, so required slots must be pre-allocated, or implementations must suppress out-of-memory errors.

JS_ErrorFromException
syntax jserrorreport * js_errorfromexception(jscontext *cx, js::handleobject obj); name type description cx jscontext * pointer to a js context whose errors should be reported via your function.

JS_FlattenString
to catch errors, an opaque jsflatstring type is returned.

JS_GetErrorPrototype
syntax jsobject * js_geterrorprototype(jscontext *cx); name type description cx jscontext * pointer to a js context whose errors should be reported via your function.

JS_HasArrayLength
this function differs from js_getarraylength in the treatment of errors and unusual cases, like when an object's length is negative or not a number.

JS_ReportError
description js_reporterror is the simplest jsapi function for reporting errors.

JS_SetErrorReporter
syntax jserrorreporter js_geterrorreporter(jsruntime *rt); jserrorreporter js_seterrorreporter(jsruntime *rt, jserrorreporter er); name type description cx jsruntime * pointer to a js runtime whose errors should be reported via your function.

JS_SetOptions
mxr id search for jsoption_extra_warnings jsoption_werror convert warnings to errors.

SpiderMonkey 1.8.5
applications must use js_getstringcharsandlength or js_encodestring/js_free and check for errors.

Running Automated JavaScript Tests
the test is considered to pass if the exit code of the js shell is zero (i.e., js didn't crash and there were no js errors).

Setting up CDT to work on SpiderMonkey
unfortunately, there are also large parts that are not properly indexed, leading to errors and warnings being shown for perfectly valid code, but i find that the parts that do work do so nicely enough to make it totally worth it.

Web Replay
seek to console messages errors and logged messages in the console developer tool can be clicked on to cause the tab to seek to the point in the recording where the error was generated or the message was logged.

A Web PKI x509 certificate primer
error codes in firefox here are some common errors that might be encountered when working with certificates in firefox.

The Publicity Stream API
possible error codes include: denied - if the user refuses to publicize the activity permissiondenied - if the publicizing site is not allowed to post to the publicity stream networkerror - if the publicity server is unreachable activityparseerror - if the activity contains syntax errors (not proper json) invalidactivity - if the activity contains semantic errors (i.e.

Aggregating the In-Memory Datasource
}; very painful, prone to errors, and fragile as the interfaces are still in flux (a wee bit).

How to build an XPCOM component in JavaScript
for code outside the tree note: on windows if you download the gecko sdk without the whole build tree, you will be missing some required dlls for xpidl.exe and it will run with no errors but not do anything.

Finishing the Component
this can prevent many errors like this.

Packaging WebLock
// register the new ui with the mozilla chrome registry registerchrome(content, getfolder(cf,"weblock.xpi"),"weblock"); registerchrome(skin, getfolder(cf, "weblock.xpi"),"weblock"); // perform the installation if there are no errors if (err==success) performinstall(); else cancelinstall(err); the weblock trigger script the trigger script is the script placed on a web page that actually initiates an xpinstall installation and calls the installation script that appears in the xpi.

Starting WebLock
assuming there weren't any unexpected errors, the variable catman holds the nsicategorymanager interface pointer, which you can use to add the component as a startup observer by calling a method on the nsicategorymanager.

Detailed XPCOM hashtable guide
the c++ wrappers for pldhash (see below) are often much easier and safer to use in c++ code, as many potential casting errors are easily avoided.

Introduction to XPCOM for the DOM
warning: this document has not yet been reviewed by the dom gurus, it might contain some errors.

Components.results
components.results is a read-only object whose properties are the names listed as the first parameters of the macros in js/xpconnect/src/xpc.msg (also at table of errors), with the value of each corresponding to that constant's value.

Components.utils.import
syntax components.utils.import(url [, scope]); // or, if you use a tool such as jslint which reports compiler errors for the above, components.utils["import"](url [, scope]); parameters url a string of the url of the script to be loaded.

Components.utils
werror boolean warnings should be treated as errors.

Components.utils.reportError
function mydump(amessage) { var consoleservice = components.classes["@mozilla.org/consoleservice;1"] .getservice(components.interfaces.nsiconsoleservice); consoleservice.logstringmessage("my component: " + amessage); } firefox 3: the error console will not display chrome errors by default.

Language bindings
the scriptable methods on the nsicomponentmanager interface can be called directly on this object.components.resultscomponents.results is a read-only object whose properties are the names listed as the first parameters of the macros in js/xpconnect/src/xpc.msg (also at table of errors), with the value of each corresponding to that constant's value.components.returncodecomponents.stackcomponents.stack is a read only property of type nsistackframe (idl definition) that represents a snapshot of the current javascript callstack.

NS_InitXPCOM2
some of the possible errors are documented below: ns_error_not_initialized indicates that static globals were not yet initialized, which may happen if this method is called before xpcom's static initialization code executes.

NS_InitXPCOM3
some of the possible errors are documented below: ns_error_not_initialized indicates that static globals were not yet initialized, which may happen if this method is called before xpcom's static initialization code executes.

RefPtr
nsifoo> foo; and for concrete classes: refptr<nsfoo> foo; // class that implements nsifoo; refptr<bar> bar; // some random class that i want ref-counted but has nothing to do with xpcom: // just implement addref() and release() and it will work with refptr it is important that nscomptr is not used to hold a pointer to a concrete class since this can cause compile time errors or runtime errors.

imgIDecoderObserver
unfortunately, this is currently the only way to signal decoding errors to consumers, and the only decoding errors that consumers care about (indeed, the only ones that they're prepared to hear about) are failures to instantiate the decoder (<img src="foo.html"> for example).

jsdIStackFrame
warnings reported as errors.

mozIStorageError
the mozistorageerror interface represents errors returned by the storage api, offering attributes to obtain the error code as well as a human-readable error message corresponding to the error that occurred.

mozIStorageStatement
mozistoragependingstatement executeasync( [optional] mozistoragestatementcallback acallback ); parameters acallback a callback object that will be notified of progress, errors, and query completion.

nsIArray
exceptions thrown ns_error_failure if the array is empty (to make it easy to detect errors).

nsIClipboardDragDropHooks
if any errors occur (without setting the boolean result) the default action will occur.

nsIClipboardOwner
it results into a ns_ok if there are no errors.

nsICommandLineRunner
all other errors thrown by handlers will be silently ignored.

nsIConsoleService
it is used to log various messages, warnings, and errors and to obtain the logged messages.

nsIDNSService
speculative requests return errors if prefetching is disabled by configuration.

nsIDOMFileError
the nsidomfileerror interface describes errors that occur while using the dom file api.

nsIDOMGeoPositionErrorCallback
the nsidomgeopositionerrorcallback interface is used to represent an object that receives callback notifications when geolocation errors occur.

nsIDOMParser
cases where these values matter: if you don't specify the document uri by calling init() after creating the parser via createinstance() the created documents will use a moz-nullprincipal:{<guid>} uri, which will show in the error console in parsing errors, in particular.

nsIException
for example, standard language errors would generally have the same location as their top stack entry.

nsIFileInputStream
this means that any errors that might happen when this flag is not set would happen during the first read.

nsIFileOutputStream
this means that any errors that might happen when this flag is not set would happen during the first write, and if the file is to be created, it will not appear on the disk until the first write.

nsINavHistoryService
see this code for how a function to add visits and handle errors using the new api could look like.

nsIRequest
users should normally pass ns_binding_aborted, although other errors may also be passed.

nsIScriptError
js/xpconnect/idl/nsiscripterror.idlscriptable represents javascript errors and warnings for use by the console service.

nsIScriptError2
js/src/xpconnect/idl/nsiscripterror.idlscriptable represents javascript errors and warnings for use by the console service; augments nsiscripterror by adding a way to initialize the error with the window id of the outer window with which the error is associated.

nsISessionStore
check with canrestorelastsession first to avoid thrown errors.

nsISmsRequestManager
ageinlist(in long arequestid); void notifyreadmessagelistfailed(in long arequestid, in long aerror); void notifysmsdeleted(in long arequestid, in bool adeleted); void notifysmsdeletefailed(in long arequestid, in long aerror); void notifysmssendfailed(in long arequestid, in long aerror); void notifysmssent(in long arequestid, in nsidommozsmsmessage amessage); constants all sms related errors that could apply to smsrequest objects.

nsIStackFrame
for example, standard language errors would generally have the same location as their top stack entry.

nsIStringBundleService
this is mapped into a string id and and used in the string lookup process (see nsierrorservice).

nsITaskbarPreviewController
note: it's guaranteed that width ÷ height will equal the thumbnailaspectratio, within the margin of rounding errors.

nsIToolkitProfileService
the profile list file is constructed in memory, then written out as one large chunk, in order to reduce the risk of the profile list file being corrupted by disk errors.

nsITransportEventSink
astatus the transport status (resolvable to a string using nsierrorservice).

nsIURIFixup
createfixupuri() converts the specified string into a uri, first attempting to correct any errors in the syntax or other vagaries.

nsIWebProgressListener
note: astatus may be a success code even for server generated errors, such as the http 404 file not found error.

nsIWebSocketListener
in the case of errors, onstop() may be called without this method ever getting called.

nsIXULTemplateQueryProcessor
only fatal errors should be thrown, or ns_error_unexpected if generateresults() has already been called.

nsIXmlRpcClient
return value will be converted as follows: i4 or int: nsisupportsprint32 boolean: nsisupportsprbool string: nsisupportscstring double: nsisupportsdouble datetime.iso8601: nsisupportsprtime base64: nsisupportscstring array: nsisupportsarray struct: nsidictionary faults (server side errors) are indicated by returning ns_error_failure.

XPCOM Interface Reference
nloadhistorynsidownloadmanagernsidownloadmanageruinsidownloadobservernsidownloadprogresslistenernsidownloadernsidragdrophandlernsidragservicensidragsessionnsidroppedlinkhandlernsidroppedlinkitemnsidynamiccontainernsieditornsieditorboxobjectnsieditordocshellnsieditorimesupportnsieditorloggingnsieditormailsupportnsieditorobservernsieditorspellchecknsieffectivetldservicensienumeratornsienvironmentnsierrorservicensieventlistenerinfonsieventlistenerservicensieventsourcensieventtargetnsiexceptionnsiextensionmanagernsiexternalhelperappservicensiexternalprotocolservicensiexternalurlhandlerservicensiftpchannelnsiftpeventsinknsifactorynsifavicondatacallbacknsifaviconservicensifeednsifeedcontainernsifeedelementbasensifeedentrynsifeedgeneratornsifeedpersonnsifeedprocessornsifeedprogresslistenernsifeedresult...

NS_ASSERTION
an assertion failure should be thrown on critical program errors only.

NS_ERROR
this macro is meant for critical errors; like assertions, ns_errors should not be reachable.

NS_WARNING
contrary to ns_error this is meant for noncritical errors.

Performance
this will lead to errors that say "database is encrypted" because the tool is not able to recognize the file format.

Storage
check for errors.

XPCOM
if you have a class that you think is involved in a cyclical-ownership leak, this page is for you.introduction to xpcom for the domwarning: this document has not yet been reviewed by the dom gurus, it might contain some errors.language bindingsan xpcom language binding is a bridge between a particular language and xpcom to provide access to xpcom objects from that language, and to let modules written in that language be used as xpcom objects by all other languages for which there are xpcom bindings.monitoring http activitygecko includes the nsihttpactivityobserver interface, which you can implement in your code to moni...

XPIDL
clang and gcc) will reports errors if these results are not used.

Thunderbird Binaries
warning: whilst developers try to ensure that nightly builds are stable, it is possible that errors can get into nightly builds that can destroy your data or harm it.

WebIDL bindings
the list of allowed typeerrors and corresponding messages is in dom/bindings/errors.msg.

CData
here is a method to read "malformed", it attempts to do readstring on it, if it errors then it tries to read it in another way, so this is an alternative to readstringreplacemalformed, it is an attempt at readingmalformed function readaschar8thenaschar16(stringptr, known_len, jschar) { // when reading as jschar it assumes max length of 500 // stringptr is either char or jschar, if you know its jschar for sure, pass 2nd arg as true // if known_len is passed, then assum...

Mozilla
error codes returned by mozilla apis the following tables list errors that can occur when calling various mozilla apis.

Constants - Plugins
error codes code value description nperr_no_error 0 no errors occurred.

Set a conditional breakpoint - Firefox Developer Tools
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
tep 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.

Debugger.Memory - Firefox Developer Tools
the owning debugger’s uncaughtexceptionhandler is still fired for errors thrown in debugger.memory hooks.

Debugger - Firefox Developer Tools
for example, an uncaught exception hook may have access to browser-level features like the alert function, which this api’s implementation does not, making it possible to present debugger errors to the developer in a way suited to the context.) debugger handler functions each debugger instance inherits accessor properties with which you can store handler functions for spidermonkey to call when given events occur in debuggee code.

Debugger-API - Firefox Developer Tools
errors throw proper javascript exceptions.

The Firefox JavaScript Debugger - Firefox Developer Tools
set a logpoint set watch expressions reference keyboard shortcuts source map errors ...

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.

Index - Firefox Developer Tools
137 source map errors debugger, debugging, dev tools, reference, source maps, tools source maps are json files providing a way to associate transformed sources, as seen by the browser, with their original sources, as written by the developer.

Network request list - Firefox Developer Tools
regexp:\d{5} regexp:mdn|mozilla for example, to find all 404, not found, errors, you can type "404" into the search and auto-complete suggests "status-code:404" so you'll end up with something like this: search in requests use the search panel to run a full-text search on headers and content.

Shader Editor - Firefox Developer Tools
for example, you can modify the colors: the editor highlights syntax errors in your code: if you hover over the cross shown next to a line containing an error, you'll see more details about the problem: ...

Validators - Firefox Developer Tools
html tidy html tidy is a tool that can be used to report errors in an html page and to format web pages for better reading.

Web Console UI Tour - Firefox Developer Tools
filter categories: you can click a filter category (such as errors, warnings, css, or xhr) to display just those types of messages.

Web Console - Firefox Developer Tools
the web console: logs information associated with a web page: network requests, javascript, css, security errors and warnings as well as error, warning and informational messages explicitly logged by javascript code running in the page context enables you to interact with a web page by executing javascript expressions in the context of the page user interface of the web console parts of the web console ui.

Animation.finish() - Web APIs
interfaceelement.addeventlistener("mousedown", function() { try { player.finish(); } catch(e if e instanceof invalidstate) { console.log("finish() called on paused or finished animation."); } catch(e); logmyerrors(e); //pass exception object to error handler } }); the following example finishes all the animations on a single element, regardless of their direction of playback.

BasicCardRequest - Web APIs
}); } catch (e) { // catch any other errors.

BasicCardResponse - Web APIs
}); } catch (e) { // catch any other errors.

BroadcastChannel: messageerror event - Web APIs
bubbles no cancelable no interface messageevent event handler property onmessageerror examples this code uses addeventlistener to listen for messages and errors: const channel = new broadcastchannel('example-channel'); channel.addeventlistener('message', (event) => { received.textcontent = event.data; }); channel.addeventlistener('messageerror', (event) => { console.error(event); }); the same, but using the onmessage and onmessageerror event handler properties: const channel = new broadcastchannel('example-channel'); channel.onmessage = (event) => { received.textcontent = event.data; }; channel.onmess...

Cache - Web APIs
return fetch(event.request.clone()).then(function(response) { console.log(' response for %s from network is: %o', event.request.url, response); if (response.status < 400 && response.headers.has('content-type') && response.headers.get('content-type').match(/^font\//i)) { // this avoids caching responses that we know are errors (i.e.

CanvasRenderingContext2D.createImageData() - Web APIs
errors thrown indexsizeerror thrown if either of the width or height arguments is zero.

CanvasRenderingContext2D.putImageData() - Web APIs
errors thrown notsupportederror thrown if any of the arguments is infinite.

Constraint validation API - Web APIs
lements listed below with a number of new properties and methods (elements that can have a form attribute that indicates their form owner): htmlbuttonelement htmlfieldsetelement htmlinputelement htmlobjectelement htmloutputelement htmlselectelement htmltextareaelement properties validity a read-only property that returns a validitystate object, whose properties represent validation errors for the value of that element.

CustomElementRegistry.define() - Web APIs
note: you'll often get notsupportederrors thrown that seem like define() is failing, but instead it is likely a problem with element.attachshadow().

DOMException - Web APIs
note: because historically the errors were identified by a numeric value that corresponded with a named variable defined to have that value, some of the entries below indicate the legacy code value and constant name that were used in the past.

ErrorEvent - Web APIs
the errorevent interface represents events providing information related to errors in scripts or in files.

FeaturePolicy.getAllowlistForFeature() - Web APIs
errors the function will raise a warning if the specified feature policy directive name is not known.

Using Fetch - Web APIs
the following example shows one way to do this by creating a line iterator (for simplicity, it assumes the text is utf-8, and doesn't handle fetch errors).

FileSystemDirectoryEntry.getDirectory() - Web APIs
errors if an error occurs and an errorcallback was specified, it gets called with a single parameter: a fileerror object describing the error.

FileSystemDirectoryEntry.getFile() - Web APIs
errors if an error occurs and an errorcallback was specified, it gets called with a single parameter: a fileerror object describing the error.

FileSystemDirectoryEntry.removeRecursively() - Web APIs
errors if an error occurs and an errorcallback was specified, it gets called with a single parameter: a fileerror object describing the error.

FileSystemEntry.copyTo() - Web APIs
errors fileerror.invalid_modification_err the requested operation involves an impossible change, such as moving a directory inside itself or one of its own child directories, or copying an item within the same directory without renaming it.

FileSystemEntry.getMetadata() - Web APIs
errors fileerror.not_found_err the filesystementry refers to an item which doesn't exist.

FileSystemEntry.getParent() - Web APIs
errors fileerror.invalid_state_err the operation failed because the file system's state doesn't permit it.

FileSystemEntry.moveTo() - Web APIs
errors fileerror.invalid_modification_err the requested operation involves an impossible change, such as moving a directory inside itself or one of its own child directories, or copying an item within the same directory without renaming it.

FileSystemEntry.remove() - Web APIs
errors fileerror.invalid_modification_err the specified entry was the file system's root directory, or the specified entry is a directory which isn't empty.

FileSystemFileEntry.file() - Web APIs
editor's note: we need to find out what kinds of errors can occur and document them.

Using the Geolocation API - Web APIs
handling errors the error callback function, if provided when calling getcurrentposition() or watchposition(), expects a geolocationpositionerror object instance as its first parameter.

GlobalEventHandlers.onerror - Web APIs
error events are fired at various targets for different kinds of errors: when a javascript runtime error (including syntax errors and exceptions thrown within handlers) occurs, an error event using interface errorevent is fired at window and window.onerror() is invoked (as well as handlers attached by window.addeventlistener (not only capturing)).

HTMLImageElement - Web APIs
errors if an error occurs while trying to load or render the image, and an onerror event handler has been configured to handle the error event, that event handler will get called.

HTMLMediaElement.error - Web APIs
syntax var myerror = htmlmediaelement.error; value a mediaerror object describing the most recent error to occur on the media element or null if no errors have occurred.

HTMLMediaElement.play() - Web APIs
possible errors include: notallowederror the user agent (browser) or operating system doesn't allow playback of media in the current context or situation.

HTMLTableElement.deleteRow() - Web APIs
return value no return value errors thrown if the number of the row to delete, specified by the parameter, is greater or equal to the number of available rows, or if it is negative and not equal to the special index -1, representing the last row of the table, the exception index_size_err is thrown.

IDBDatabaseException - Web APIs
unknown_err 1 the operation failed for reasons unrelated to the database itself, and it is not covered by any other error code--for example, a failure due to disk io errors.

databases - Web APIs
other error specification does not describe all possible errors.

IDBRequest.error - Web APIs
a failure due to disk io errors is such an example.

ImageData() - Web APIs
errors thrown indexsizeerror thrown if array is specified, but its length is not a multiple of (4 * width) or (4 * width * height).

LargestContentfulPaint - Web APIs
// catch errors since some browsers throw when using the new `type` option.

LayoutShift - Web APIs
// catch errors since some browsers throw when using the new `type` option.

LocalFileSystemSync - Web APIs
example //taking care of the browser-specific prefix window.requestfilesystemsync = window.requestfilesystemsync || window.webkitrequestfilesystemsync; // the first parameter defines the type of storage: persistent or temporary // next, set the size of space needed (in bytes) // initfs is the success callback // and the last one is the error callback // for denial of access and other errors.

MediaDevices.getDisplayMedia() - Web APIs
possible errors are: aborterror an error or failure that doesn't match any of the other exceptions below occurred.

MediaRecorder: error event - Web APIs
bubbles no cancelable no interface mediarecordererrorevent event handler property onerror for details of the all the possible errors see the documentation for the event handler property: onerror.

MediaRecorder.onwarning - Web APIs
the mediarecorder.onwarning event handler (part of the mediarecorder api) handles the recordingwarning event, allowing you to run code in response to non-fatal errors being thrown during media recording via a mediarecorder, which don't halt recording.

MediaRecorder.requestData() - Web APIs
syntax mediarecorder.requestdata() errors an invalidstate error is raised if the requestdata() method is called while the mediarecorder object’s mediarecorder.state is not "recording" — the media cannot be captured if recording is not occurring.

MediaRecorder.resume() - Web APIs
syntax mediarecorder.resume() errors an invalidstate error is raised if the resume() method is called while the mediarecorder object’s mediarecorder.state is "inactive" — the recording cannot be resumed if it is not already paused; if mediarecorder.state is already "recording", resume() has no effect.

MediaRecorder.stop() - Web APIs
syntax mediarecorder.stop() errors an invalidstate error is raised if the stop() method is called while the mediarecorder object’s mediarecorder.state is "inactive" — it makes no sense to stop media capture if it is already stopped.

MediaRecorderErrorEvent() - Web APIs
in general, you won't create these yourself; they are delivered to your implementation of mediarecorder.onerror when errors occur while recording media.

MediaRecorderErrorEvent.error - Web APIs
example this function creates and returns a mediarecorder for a given mediastream, configured to buffer data into an array and to watch for errors.

MediaRecorderErrorEvent - Web APIs
the mediarecordererrorevent interface represents errors returned by the mediastream recording api.

MediaStream Recording API - Web APIs
mediarecordererrorevent the interface that represents errors thrown by the mediastream recording api.

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.

Using the Media Capabilities API - Web APIs
handling errors in our video decoding example, a typeerror would be raised if the media configuration passed to the decodinginfo() method was invalid.

Capabilities, constraints, and settings - Web APIs
figuring this out has often been difficult, and has usually involved looking at some combination of which user agent (or browser) you're running on, which version it is, looking to see if certain objects exist, trying to see whether various things work or not and determining what errors occur, and so forth.

MessagePort: messageerror event - Web APIs
ps://example.org'; const messagecontrol = document.queryselector('#message'); const channelmessagebutton = document.queryselector('#channel-message'); channelmessagebutton.addeventlistener('click', () => { myport.postmessage(messagecontrol.value); }) targetframe.postmessage('init', targetorigin, [channel.port2]); the target can receive the port and start listening for messages and message errors on it using code like this: window.addeventlistener('message', (event) => { const myport = event.ports[0]; myport.addeventlistener('message', (event) => { received.textcontent = event.data; }); myport.addeventlistener('messageerror', (event) => { console.error(event.data); }); myport.start(); }); note that the listener must call messageport.start() bef...

Node.insertBefore() - Web APIs
living standard fixes errors in the insertion algorithm dom4the definition of 'node.insertbefore' in that specification.

Node.removeChild() - Web APIs
this will also happen if child was in fact a child of element at the time of the call, but was removed by an event handler invoked in the course of trying to remove the element (e.g., blur.) errors thrown the method throws an exception in 2 different ways: if the child was in fact a child of element and so existing on the dom, but was removed the method throws the following exception: uncaught notfounderror: failed to execute 'removechild' on 'node': the node to be removed is not a child of this node.

NodeList - Web APIs
example it's possible to loop over the items in a nodelist using a for loop: for (let i = 0; i < mynodelist.length; i++) { let item = mynodelist[i]; } don't use for...in to enumerate the items in nodelists, since they will also enumerate its length and item properties and cause errors if your script assumes it only has to deal with element objects.

PaymentDetailsUpdate.error - Web APIs
syntax errorstring = paymentdetailsupdate.error; paymentdetailsupdate.error = errorstring; value a domstring specifying the string to display to the user if the information specified in the paymentdetailsupdate doesn't provide any valid shipping options.

PaymentRequest.PaymentRequest() - Web APIs
}); } catch (e) { // catch any other errors.

PaymentRequest: shippingaddresschange event - Web APIs
paymentrequest = new paymentrequest(methoddata, details, options); paymentrequest.addeventlistener("shippingaddresschange", event => { let detailsupdate = checkaddress(paymentrequest.shippingaddress); event.updatewith(detailsupate); }, false); const checkaddress = theaddress => { let detailsupdate = {}; // check the address, return a paymentdetailsupdate object // with any changes or errors.

PaymentResponse.onpayerdetailchange - Web APIs
ame(payername)); oldpayername = payername; } if (oldpayeremail !== payeremail) { promisestovalidate.push(validateemail(payeremail)); oldpayeremail = payeremail; } if (oldpayerphone !== payerphone) { promisestovalidate.push(validatephone(payerphone)); oldpayerphone = payerphone; } // as each validation promise resolves, add the results of the // validation to the errors list const errors = await promise.all(promisestovalidate).then(results => results.reduce((errors, result), object.assign(errors, result)) ); // if we found any errors, wait for them to be corrected if (object.getownpropertynames(errors).length) { await response.retry(errors); } else { // we have a good payment; send the data to the server await fetch("/pay-for-things/...

PaymentResponse: payerdetailchange event - Web APIs
ame(payername)); oldpayername = payername; } if (oldpayeremail !== payeremail) { promisestovalidate.push(validateemail(payeremail)); oldpayeremail = payeremail; } if (oldpayerphone !== payerphone) { promisestovalidate.push(validatephone(payerphone)); oldpayerphone = payerphone; } // as each validation promise resolves, add the results of the // validation to the errors list const errors = await promise.all(promisestovalidate).then(results => results.reduce((errors, result), object.assign(errors, result)) ); // if we found any errors, wait for them to be corrected if (object.getownpropertynames(errors).length) { await response.retry(errors); } else { // we have a good payment; send the data to the server await fetch("/pay-for-things/...

Using the Payment Request API - Web APIs
ccess: paymentresponse.complete('success') .then(function() { // for demo purposes: intropanel.style.display = 'none'; successpanel.style.display = 'block'; }); }).catch(function(error) { if (error.code == domexception.not_supported_err) { window.location.href = 'https://bobpay.xyz/#download'; } else { // other kinds of errors; cancelled or failed payment.

PromiseRejectionEvent() - Web APIs
it also becomes easier to write a global handler for errors.

RTCDataChannel: error event - Web APIs
*/ } note: since rtcerror is not one of the legacy errors, the value of rtcerror.code is always 0.

RTCError - Web APIs
it's based upon the standard domexception interface that describes general dom errors.

RTCErrorEvent - Web APIs
description there are other data types used for error events in webrtc, as needed for errors with special information sharing requirements.

RTCPeerConnection.addIceCandidate() - Web APIs
exceptions when an error occurs while attempting to add the ice candidate, the promise returned by this method is rejected, returning one of the errors below as the name attribute in the specified domexception object passed to the rejection handler.

RTCPeerConnection.close() - Web APIs
make sure that you delete all references to the previous rtcpeerconnection before attempting to create a new one that connects to the same remote peer, as not doing so might result in some errors depending on the browser.

RTCPeerConnection.createAnswer() - Web APIs
promise.catch() is used to trap and handle errors.

RTCPeerConnection.createOffer() - Web APIs
use promise.catch() to trap and handle errors.

RTCPeerConnection.getStats() - Web APIs
exceptions this method does not throw exceptions; instead, it rejects the returned promise with one of the following errors: invalidaccesserror there is no rtcrtpsender or rtcrtpreceiver whose track matches the specified selector, or selector matches more than one sender or receiver.

RTCPeerConnection.onicecandidateerror - Web APIs
example pc.onicecandidateerror = function(event) { if (event.errorcode >= 300 && event.errorcode <= 699) { // stun errors are in the range 300-699.

RTCPeerConnection.oniceconnectionstatechange - Web APIs
pc.oniceconnectionstatechange = function(event) { if (pc.iceconnectionstate === "failed" || pc.iceconnectionstate === "disconnected" || pc.iceconnectionstate === "closed") { // handle the failure } }; of course, "disconnected" and "closed" don't necessarily indicate errors; these can be the result of normal ice negotiation, so be sure to handle these properly (if at all).

RTCPeerConnection.onidpassertionerror - Web APIs
you should instead detect idp assertion errors by handling rejection of the promise returned by rtcpeerconnection.peeridentity.

RTCPeerConnection.onidpvalidationerror - Web APIs
you should instead detect idp validation errors by watching for the promise returned by rtcpeerconnection.peeridentity to be rejected.

RTCRtpStreamStats - Web APIs
this is a fairly technical part of how codecs work and while the higher this value is, the more errors occurred in the stream, generally most of the time this value is only interesting to very intensively hardcore media developers.

ReadableStream - Web APIs
readablestream.pipeto() pipes the current readablestream to a given writablestream and returns a promise that fulfills when the piping process completes successfully, or rejects if any errors were encountered.

ReadableStreamBYOBReader.closed - Web APIs
the closed read-only property of the readablestreambyobreader interface returns a promise that fulfills if the stream becomes closed or the reader's lock is released, or rejects if the stream errors.

ReadableStreamBYOBReader - Web APIs
returns a promise that fulfills if the stream becomes closed or the reader's lock is released, or rejects if the stream errors.

ReadableStreamDefaultReader.closed - Web APIs
the closed read-only property of the readablestreamdefaultreader interface returns a promise that fulfills if the stream becomes closed or the reader's lock is released, or rejects if the stream errors.

ReadableStreamDefaultReader - Web APIs
returns a promise that fulfills if the stream becomes closed or the reader's lock is released, or rejects if the stream errors.

Request() - Web APIs
errors type description typeerror since firefox 43, request() will throw a typeerror if the url has credentials, such as http://user:password@example.com.

Using the Screen Capture API - Web APIs
ment.getelementbyid("stop"); // options for getdisplaymedia() var displaymediaoptions = { video: { cursor: "always" }, audio: false }; // set event listeners for the start and stop buttons startelem.addeventlistener("click", function(evt) { startcapture(); }, false); stopelem.addeventlistener("click", function(evt) { stopcapture(); }, false); logging content to make logging of errors and other issues easy, this example overrides certain console methods to output their messages to the <pre> block whose id is log.

SensorErrorEvent.SensorErrorEvent() - Web APIs
the sensorerrorevent constructor creates a new sensorerrorevent object which provides information about errors thrown by any of the interfaces based on sensor.

SensorErrorEvent - Web APIs
the sensorerrorevent interface of the sensor apis provides information about errors thrown by a sensor or related interface.

Server-sent events - Web APIs
interfaces eventsource defines all the features that handle connecting to a server, receiving events/data, errors, closing a connection, etc.

SpeechSynthesisErrorEvent - Web APIs
the speechsynthesiserrorevent interface of the web speech api contains information about any errors that occur while processing speechsynthesisutterance objects in the speech service.

Streams API - Web APIs
there are more advantages too — you can detect when streams start or end, chain streams together, handle errors and cancel streams as required, and react to the speed of the stream is being read at.

SubtleCrypto - Web APIs
errors in security system design and implementation can make the security of the system completely ineffective.

TrackDefault.TrackDefault() - Web APIs
errors when this constructor is invoked, the following errors can occur: error explanation invalidaccesserror the supplied language is not a valid language code, e.g.

TrackDefaultList.TrackDefault() - Web APIs
errors no specific errors are returned, but if the supplied index is great than or equal to trackdefaultlist.length, the operation will return undefined.

WEBGL_lose_context.restoreContext() - Web APIs
syntax gl.getextension('webgl_lose_context').restorecontext(); errors thrown invalid_operation if the context was not lost.

WebGLRenderingContext.enableVertexAttribArray() - Web APIs
errors to check for errors after calling enablevertexattribarray(), call geterror().

WebGLRenderingContext.getUniformLocation() - Web APIs
errors the following errors may occur; to check for errors after getuniformlocation() returns, call geterror().

WebGLRenderingContext.makeXRCompatible() - Web APIs
exceptions this method doesn't throw traditional exceptions; instead, the promise rejects with one of the following errors as the value passed into the rejection handler: aborterror switching the context over to the webxr-compatible context failed.

WebGLRenderingContext.viewport() - Web APIs
errors thrown if either width or height is a negative value, a gl.invalid_value error is thrown.

A basic 2D WebGL animation example - Web APIs
the source code is sent into the new shader by passing it into gl.shadersource(), and then the shader is compiled using gl.compileshader() compile errors are logged to the console.

Establishing a connection: The WebRTC perfect negotiation pattern - Web APIs
errors are, as before, ignored if we have just discarded an offer.

Lifetime of a WebRTC session - Web APIs
information exchanged during signaling there are three basic types of information that need to be exchanged during signaling: control messages used to set up, open, and close the communication channel, and to handle errors.

A simple RTCDataChannel sample - Web APIs
the catch() calls a routine that handles any errors that occur.

Using DTMF with WebRTC - Web APIs
logging a simple log() function is used throughout the code to append html to a <div> box for displaying status and errors to the user.

Using WebRTC data channels - Web APIs
for example, both firefox and google chrome use the usrsctp library to implement sctp, but there are still situations in which data transfer on an rtcdatachannel can fail due to differences in how they call the library and react to errors it returns.

WebSocket: error event - Web APIs
bubbles no cancelable no interface event event handler property onerror examples // create websocket connection const socket = new websocket('ws://localhost:8080'); // listen for possible errors socket.addeventlistener('error', function (event) { console.log('websocket error: ', event); }); specifications specification status html living standardthe definition of 'websocket error' in that specification.

Writing WebSocket client applications - Web APIs
connection errors if an error occurs while attempting to connect, first a simple event with the name error is sent to the websocket object (thereby invoking its onerror handler), and then the closeevent is sent to the websocket object (thereby invoking its onclose handler) to indicate the reason for the connection's closing.

Background audio processing using AudioWorklet - Web APIs
this avoids errors due to overrunning these arrays.

Web Crypto API - Web APIs
errors in security system design and implementation can make the security of the system completely ineffective.

Using the Web Speech API - Web APIs
we also use a speechrecognition.onspeechend handler to stop the speech recognition service from running (using speechrecognition.stop()) once a single word has been recognised and it has finished being spoken: recognition.onspeechend = function() { recognition.stop(); } handling errors and unrecognised speech the last two handlers are there to handle cases where speech was recognised that wasn't in the defined grammar, or an error occured.

Web Speech API - Web APIs
speechsynthesiserrorevent contains information about any errors that occur while processing speechsynthesisutterance objects in the speech service.

Using Web Workers - Web APIs
handling errors when a runtime error occurs in the worker, its onerror event handler is called.

Worklet.addModule() - Web APIs
exceptions if addmodule() fails, it rejects the promise, delivering one of the following errors to the rejection handler.

WritableStreamDefaultWriter.closed - Web APIs
the closed read-only property of the writablestreamdefaultwriter interface returns a promise that fulfills if the stream becomes closed or the writer's lock is released, or rejects if the stream errors.

WritableStreamDefaultWriter - Web APIs
returns a promise that fulfills if the stream becomes closed or the writer's lock is released, or rejects if the stream errors.

XMLHttpRequest.status - Web APIs
browsers also report a status of 0 in case of xmlhttprequest errors.

XRPose.emulatedPosition - Web APIs
this is because emulating a position based on accelerometer inputs and models tends to introduce minor errors which accumulate over time.

XRWebGLLayer() - Web APIs
exceptions invalidstateerror the new xrwebgllayer could not be created due to one of a number of possible state errors: the xrsession specified by session has already been stopped.

Using the alert role - Accessibility
<h2 role="alert">your form could not be submitted because of 3 validation errors.</h2> example 2: dynamically adding an element with the alert role this snippet dynamically creates an element with an alert role and adds it to the document structure.

Using the aria-invalid attribute - Accessibility
values vocabulary: false (default) no errors detected grammar a grammatical error has been detected.

Text labels and names - Accessibility
reference article about the <title> element is as follows: <title>&lt;title&gt;: the document title element - html: hypertext markup language</title> another example might look like so: <title>fill in your details to register — mygov services</title> to help the user, you can update the page title value to reflect significant page state changes (such as form validation problems): <title>2 errors — fill in your details to register — mygov services</title> see also <title> embedded content must be labeled make sure that elements that embed content have a title attribute that describes the embedded content.

::grammar-error - CSS: Cascading Style Sheets
all subset of css properties can be used in a rule with ::grammar-error in its selector: color background-color cursor caret-color outline and its longhands text-decoration and its associated properties text-emphasis-color text-shadow syntax ::grammar-error examples simple document grammar check in this example, eventual supporting browsers should highlight any flagged grammatical errors with the styles shown.

::spelling-error - CSS: Cascading Style Sheets
small subset of css properties can be used in a rule with ::spelling-error in its selector: color background-color cursor caret-color outline and its longhands text-decoration and its associated properties text-emphasis-color text-shadow syntax ::spelling-error examples simple document spell check in this example, eventual supporting browsers should highlight any flagged spelling errors with the styles shown.

:invalid - CSS: Cascading Style Sheets
/* selects any invalid <input> */ input:invalid { background-color: pink; } this pseudo-class is useful for highlighting field errors for the user.

Shapes From Images - CSS: Cascading Style Sheets
devtools can help you to identify cors errors.

Tools - CSS: Cascading Style Sheets
other tools css animation - stylie to check the device display information (helpful in responsive web design) - mydevice.io css menus - cssmenumaker.com a mighty, modern css linter that helps you enforce consistent conventions and avoid errors in your stylesheets - stylelint ...

shape-outside - CSS: Cascading Style Sheets
if this results in network errors such that there is no valid fallback image, the effect is as if the value none had been specified.

Introduction to HTML5 - Developer guides
now, faced with errors in the mark-up, all compliant browsers must behave exactly in the same way.

<a>: The Anchor element - HTML: Hypertext Markup Language
these bogus href values cause unexpected behavior when copying/dragging links, opening links in a new tab/window, bookmarking, or when javascript is loading, errors, or is disabled.

<audio>: The Embed Audio element - HTML: Hypertext Markup Language
this also provides a way to monitor the audio's fetching process so you can watch for errors or detect when enough is available to begin to play or manipulate it.

<title>: The Document Title element - HTML: Hypertext Markup Language
example <title>2 errors - your order - blue house chinese food - foodyum: online takeout today!</title> mdn understanding wcag, guideline 2.4 explanations understanding success criterion 2.4.2 | w3c understanding wcag 2.0 specifications specification status comment html living standardthe definition of '<title>' in that specification.

HTML documentation index - HTML: Hypertext Markup Language
29 spellcheck global attributes, html, reference the spellcheck global attribute is an enumerated attribute defines whether the element may be checked for spelling errors.

Using the application cache - HTML: Hypertext Markup Language
if any errors occur, the browser sends an error event, and the update halts.

Cross-Origin Resource Sharing (CORS) - HTTP
cors failures result in errors, but for security reasons, specifics about the error are not available to javascript.

CSP: child-src - HTTP
for workers, non-compliant requests are treated as fatal network errors by the user agent.

CSP: prefetch-src - HTTP
example prefetch resources do not match header given a page with the following content security policy: content-security-policy: prefetch-src https://example.com/ fetches for the following code will return network errors, as the urls provided do not match prefetch-src's source list: <link rel="prefetch" src="https://example.org/"></link> <link rel="prerender" src="https://example.org/"></link> specification specification status comment content security policy level 3the definition of 'prefetch-src' in that specification.

Index - HTTP
for workers, non-compliant requests are treated as fatal network errors by the user agent.

Large-Allocation - HTTP
examples large-allocation: 0 large-allocation: 500 troubleshooting errors the large-allocation header throws warnings or error messages when used incorrectly.

Strict-Transport-Security - HTTP
when your site is accessed over https with no certificate errors, the browser knows your site is https capable and will honor the strict-transport-security header.

A typical HTTP session - HTTP
responses are grouped into five classes: informational responses, successful responses, redirects, client errors, and servers errors.

HTTP
responses are grouped in five classes: informational responses, successful responses, redirections, client errors, and servers errors.

Grammar and types - JavaScript
note : trailing commas can create errors in older browser versions and it is a best practice to remove them.

About the JavaScript reference - JavaScript
errors chapter about specific errors, exceptions and warnings thrown by javascript.

Classes - JavaScript
strict mode the body of a class is executed in strict mode, i.e., code written here is subject to stricter syntax for increased performance, some otherwise silent errors will be thrown, and certain keywords are reserved for future versions of ecmascript.

SyntaxError: missing } after function body - JavaScript
(function() { if (true) { return false; } ); oftentimes, indenting differently or double checking indentation helps to spot these errors.

ReferenceError: assignment to undeclared variable "x" - JavaScript
errors about undeclared variable assignments occur in strict mode code only.

TypeError: invalid 'instanceof' operand 'x' - JavaScript
s instanceof vs typeof "test" instanceof ""; // typeerror: invalid 'instanceof' operand "" 42 instanceof 0; // typeerror: invalid 'instanceof' operand 0 function foo() {} var f = foo(); // foo() is called and returns undefined var x = new foo(); x instanceof f; // typeerror: invalid 'instanceof' operand f x instanceof x; // typeerror: x is not a function to fix these errors, you will either need to replace the instanceof operator with the typeof operator, or to make sure you use the function name, instead of the result of its evaluation.

DataView.prototype.getBigInt64() - JavaScript
errors thrown rangeerror thrown if the byteoffset is set such that it would read beyond the end of the view.

DataView.prototype.getBigUint64() - JavaScript
errors thrown rangeerror thrown if the byteoffset is set such that it would read beyond the end of the view.

DataView.prototype.getFloat32() - JavaScript
errors thrown rangeerror thrown if the byteoffset is set such as it would read beyond the end of the view.

DataView.prototype.getFloat64() - JavaScript
errors thrown rangeerror thrown if the byteoffset is set such as it would read beyond the end of the view.

DataView.prototype.getInt16() - JavaScript
errors thrown rangeerror thrown if the byteoffset is set such as it would read beyond the end of the view.

DataView.prototype.getInt32() - JavaScript
errors thrown rangeerror thrown if the byteoffset is set such as it would read beyond the end of the view.

DataView.prototype.getInt8() - JavaScript
errors thrown rangeerror thrown if the byteoffset is set such as it would read beyond the end of the view.

DataView.prototype.getUint16() - JavaScript
errors thrown rangeerror thrown if the byteoffset is set such as it would read beyond the end of the view.

DataView.prototype.getUint32() - JavaScript
errors thrown rangeerror thrown if the byteoffset is set such as it would read beyond the end of the view.

DataView.prototype.getUint8() - JavaScript
errors thrown rangeerror thrown if the byteoffset is set such as it would read beyond the end of the view.

DataView.prototype.setBigInt64() - JavaScript
errors thrown rangeerror thrown if the byteoffset is set such that it would store beyond the end of the view.

DataView.prototype.setBigUint64() - JavaScript
errors thrown rangeerror thrown if the byteoffset is set such that it would store beyond the end of the view.

DataView.prototype.setFloat32() - JavaScript
errors thrown rangeerror thrown if the byteoffset is set such as it would store beyond the end of the view.

DataView.prototype.setFloat64() - JavaScript
errors thrown rangeerror thrown if the byteoffset is set such as it would store beyond the end of the view.

DataView.prototype.setInt16() - JavaScript
errors thrown rangeerror thrown if the byteoffset is set such as it would store beyond the end of the view.

DataView.prototype.setInt32() - JavaScript
errors thrown rangeerror thrown if the byteoffset is set such as it would store beyond the end of the view.

DataView.prototype.setInt8() - JavaScript
errors thrown rangeerror thrown if the byteoffset is set such as it would store beyond the end of the view.

DataView.prototype.setUint16() - JavaScript
errors thrown rangeerror thrown if the byteoffset is set such as it would store beyond the end of the view.

DataView.prototype.setUint32() - JavaScript
errors thrown rangeerror thrown if the byteoffset is set such as it would store beyond the end of the view.

DataView.prototype.setUint8() - JavaScript
errors thrown rangeerror thrown if the byteoffset is set such as it would store beyond the end of the view.

Error.prototype.toSource() - JavaScript
examples using tosource calling the tosource method of an error instance (including nativeerrors) will return a string containing the source code of the error.

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).

Object.defineProperty() - JavaScript
throws a typeerror // (even though the new get does exactly the same thing) object.defineproperty(o, 'a', { value: 12 }); // throws a typeerror // ('value' can be changed when 'configurable' is false but not in this case due to 'get' accessor) console.log(o.a); // logs 1 delete o.a; // nothing happens console.log(o.a); // logs 1 if the configurable attribute of o.a had been true, none of the errors would be thrown and the property would be deleted at the end.

Object.freeze() - JavaScript
object.isfrozen(obj); // === true // now any changes will fail obj.foo = 'quux'; // silently does nothing // silently doesn't add the property obj.quaxxor = 'the friendly duck'; // in strict mode such attempts will throw typeerrors function fail(){ 'use strict'; obj.foo = 'sparky'; // throws a typeerror delete obj.foo; // throws a typeerror delete obj.quaxxor; // returns true since attribute 'quaxxor' was never added obj.sparky = 'arf'; // throws a typeerror } fail(); // attempted changes through object.defineproperty; // both statements below throw a typeerror.

Object.prototype.isPrototypeOf() - JavaScript
errors thrown typeerror a typeerror is thrown if prototypeobj is undefined or null.

Object.seal() - JavaScript
obj.quaxxor = 'the friendly duck'; // silently doesn't add the property delete obj.foo; // silently doesn't delete the property // ...and in strict mode such attempts // will throw typeerrors.

Promise.resolve() - JavaScript
resolving thenables and throwing errors // resolving a thenable object var p1 = promise.resolve({ then: function(onfulfill, onreject) { onfulfill('fulfilled!'); } }); console.log(p1 instanceof promise) // true, object casted to a promise p1.then(function(v) { console.log(v); // "fulfilled!" }, function(e) { // not called }); // thenable throws before callback // promise rejects var thenable = { then: function(resolve) { ...

Promise.prototype.then() - JavaScript
if one or both arguments are omitted or are provided non-functions, then then will be missing the handler(s), but will not generate any errors.

String.prototype.normalize() - JavaScript
errors thrown rangeerror a rangeerror is thrown if form isn't one of the values specified above.

WebAssembly - JavaScript
providing facilities to handle errors that occur in webassembly via the webassembly.compileerror()/webassembly.linkerror()/webassembly.runtimeerror() constructors.

decodeURI() - JavaScript
examples decoding a cyrillic url decodeuri('https://developer.mozilla.org/ru/docs/javascript_%d1%88%d0%b5%d0%bb%d0%bb%d1%8b'); // "https://developer.mozilla.org/ru/docs/javascript_шеллы" catching errors try { var a = decodeuri('%e0%a4%a'); } catch(e) { console.error(e); } // urierror: malformed uri sequence specifications specification ecmascript (ecma-262)the definition of 'decodeuri' in that specification.

decodeURIComponent() - JavaScript
examples decoding a cyrillic url component decodeuricomponent('javascript_%d1%88%d0%b5%d0%bb%d0%bb%d1%8b'); // "javascript_шеллы" catching errors try { var a = decodeuricomponent('%e0%a4%a'); } catch(e) { console.error(e); } // urierror: malformed uri sequence decoding query parameters from a url decodeuricomponent cannot be used directly to parse query parameters from a url.

undefined - JavaScript
// x has not been declared before if (typeof x === 'undefined') { // evaluates to true without errors // these statements execute } if (x === undefined) { // throws a referenceerror } however, there is another alternative.

Iteration protocols - JavaScript
using one is likely to result in runtime errors or buggy behavior: let nonwellformediterable = {}; nonwellformediterable[symbol.iterator] = () => 1; [...nonwellformediterable]; // typeerror: [] is not a function iterator examples simple iterator function makeiterator(array) { let nextindex = 0 return { next: function() { return nextindex < array.length ?

Object initializer - JavaScript
in non-supporting environments, these notations will lead to syntax errors.

delete operator - JavaScript
therefore, to avoid syntax errors in strict mode, you must use the delete operator in the form of delete object.property or delete object['property'].

Function expression - JavaScript
var foo = function() {} foo.name // "foo" var foo2 = foo foo2.name // "foo" var bar = function baz() {} bar.name // "baz" console.log(foo === foo2); // true console.log(typeof baz); // undefined console.log(bar === baz); // false (errors because baz == undefined) examples creating an unnamed function the following example defines an unnamed function and assigns it to x.

typeof - JavaScript
typeof /s/ === 'function'; // chrome 1-12 non-conform to ecmascript 5.1 typeof /s/ === 'object'; // firefox 5+ conform to ecmascript 5.1 errors before ecmascript 2015, typeof was always guaranteed to return a string for any operand it was supplied with.

async function - JavaScript
} foo().catch(() => {}) // attempt to swallow all errors...

break - JavaScript
block_1: { console.log('1'); break block_2; // syntaxerror: label not found } block_2: { console.log('2'); } break within functions syntaxerrors are also generated in the following code examples which use break statements within functions that are nested within a loop, or labeled block that the break statements are intended to break out of.

export - JavaScript
you can't run js modules via a file:// url — you'll get cors errors.

switch - JavaScript
d brackets let message = 'hello'; console.log(message); break; } // added brackets case 'say_hi': { // added brackets let message = 'hi'; console.log(message); break; } // added brackets default: { // added brackets console.log('empty action received.'); break; } // added brackets } this code will now output hello in the console as it should, without any errors at all.

Authoring MathML - MathML
cons: this may be harder to use: people must learn a syntax, typos in the code may easily lead to parsing or rendering errors etc the interface is not user-friendly: only code editor without immediate display of the mathematical expression.

Autoplay guide for media and Web Audio APIs - Web media technologies
any other errors are handled as appropriate.

Handling media support issues in web content - Web media technologies
detecting playback errors adapting presentation with css memory management ...

Web video codec guide - Web media technologies
this means that any errors or artifacts will compound over time, resulting in glitches or otherwise strange or unexpected deviations in the image that linger for a time.

Guide to streaming audio and video - Web media technologies
for example, because many web sites' mobile-specific content assume that mobile browsers support hls, firefox for android does as well, in order to avoid strange compatibility errors from occurring due to this assumption being incorrect.

OpenSearch description format
troubleshooting tips if there is a mistake in your search plugin xml, you could run into errors when adding a discovered plugin.

keyPoints - SVG: Scalable Vector Graphics
if there are any errors in the value specification (i.e.

keySplines - SVG: Scalable Vector Graphics
if there are any errors in the keysplines specification (bad values, too many or too few values), the animation will not occur.

SVG documentation index - SVG: Scalable Vector Graphics
if there are any errors in the keysplines specification (bad values, too many or too few values), the animation will not occur.

Namespaces crash course - SVG: Scalable Vector Graphics
it may save you from some annoying errors if you end up adding content from one of the unused namespaces at a later date.

Mixed content - Web security
to make it easier for web developers to find mixed content errors, all blocked mixed content requests are logged to the security pane of the web console, as seen below: to fix this type of error, all requests to http content should be removed and replaced with content served over https.

Index - XSLT: Extensible Stylesheet Language Transformations
2 common xslt errors xslt your server needs to send both the source and the stylesheet with a xml mime type, text/xml or application/xml.

XSLT: Extensible Stylesheet Language Transformations
common xslt errors this article lists some common problems using xslt in firefox.