XPCOMUtils.jsm
the xpcomutils.jsm javascript code module offers utility routines for javascript components loaded by the javascript component loader.
... to use this, you first need to import the code module into your javascript scope: components.utils.import("resource://gre/modules/xpcomutils.jsm"); using xpcomutils exposing a javascript class as a component using these utility methods requires four key steps: import xpcomutils.jsm, as explained previously.
...for example, if an extension named "myextension" bundles foo.jsm and bar.jsm, and foo.jsm needs to load bar.jsm, it can do so like this: components.utils.import("resource://gre/modules/xpcomutils.jsm"); xpcomutils.importrelative(this, "bar.jsm"); in other words: importrelative will only work from other code modules (such as jsm files).
... examples definelazygetter var myservices = {}; cu.import('resource://gre/modules/xpcomutils.jsm'); //set it up xpcomutils.definelazygetter(myservices, 'as', function () { return cc['@mozilla.org/alerts-service;1'].getservice(ci.nsialertsservice) }); //when you need to use it myservices.as.showalertnotification('chrome://branding/content/icon64.png', 'this was lazyloaded', 'this is a notification from myservices.as', null, null); ...

How to build an XPCOM component in JavaScript
om_apps # set to 1 if the module should be part of the gecko runtime common to all applications gre_module = 1 # the idl sources xpidlsrcs = \ helloworld.idl \ $(null) include $(topsrcdir)/config/rules.mk xpidl_flags += \ -i$(topsrcdir)/dom/interfaces/base \ -i$(topsrcdir)/dom/interfaces/events \ $(null) creating the component using xpcomutils in firefox 3 and later you can use import xpcomutils.jsm using components.utils.import to simplify the process of writing your component slightly.
...the library provides a simple example of its use in the source code (js/xpconnect/loader/xpcomutils.jsm), but here's another using this example.
... to begin, include a line at the top of your interface to import the xpcomutils library: components.utils.import("resource://gre/modules/xpcomutils.jsm"); then implement your interface the same way you did above, except with a few modifications so that xpcomutils can set it up properly: /*********************************************************** class definition ***********************************************************/ //class constructor function helloworld() { // if you only need to access your component from javascript, uncomment the following line: //this.wrappedjsobject = this; } // class definition helloworld.prototype = { // properties required for xpcom registration: classdescription: "my hello world javascript xpcom component", classid: components.id("{xxxxxxxx-xxxx-xx...
...tfactory = xpcomutils.generatensgetfactory(components); // firefox 4.0 and higher else var nsgetmodule = xpcomutils.generatensgetmodule(components); // firefox 3.x so the total simplified version of your component now looks like (of course documentation and comments aren't a bad thing, but as a template something smaller is nice to have): components.utils.import("resource://gre/modules/xpcomutils.jsm"); function helloworld() { } helloworld.prototype = { classdescription: "my hello world javascript xpcom component", classid: components.id("{xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx}"), contractid: "@dietrich.ganx4.com/helloworld;1", queryinterface: xpcomutils.generateqi([components.interfaces.nsihelloworld]), hello: function() { return "hello world!"; } }; var components ...

XPCOM changes in Gecko 2.0
if you used xpcomutils.jsm, some of this was hidden from you, but it was still there.
...for example, in your component's javascript code : components.utils.import("resource://gre/modules/xpcomutils.jsm"); function mycomponent() { } mycomponent.prototype = { // this must match whatever is in chrome.manifest!
...const nsgetfactory = xpcomutils.generatensgetfactory([mycomponent]); a component may implement backwards compatibility with gecko 1.9.2 by dynamically detecting which symbols are exported by xpcomutils.jsm and exporting the correct function: /** * xpcomutils.generatensgetfactory was introduced in mozilla 2 (firefox 4, seamonkey 2.1).
... xpcomutils.jsm changes the xpcomutils.jsm code module has been updated to let you specify the application ids of the applications you wish to register your component in.

Creating Event Targets - Archive of obsolete content
then open "index.js" and add the following code: var {cc, ci} = require("chrome"); var { xpcomutils } = require("resource://gre/modules/xpcomutils.jsm"); var bookmarkservice = cc["@mozilla.org/browser/nav-bookmarks-service;1"] .getservice(ci.nsinavbookmarksservice); var bookmarkobserver = { onitemadded: function(aitemid, afolder, aindex) { console.log("added ", bookmarkservice.getbookmarkuri(aitemid).spec); }, onitemvisited: function(aitemid, avisitid, time) { console.log("visited ", bookmarkservice.getb...
... create a new file in "lib" called "bookmarks.js", and add the following code: var { emit, on, once, off } = require("sdk/event/core"); var {cc, ci} = require("chrome"); var { xpcomutils }= require("resource://gre/modules/xpcomutils.jsm"); var bookmarkservice = cc["@mozilla.org/browser/nav-bookmarks-service;1"] .getservice(ci.nsinavbookmarksservice); var bookmarkobserver = { onitemadded: function(aitemid, afolder, aindex) { emit(exports, "added", bookmarkservice.getbookmarkuri(aitemid).spec); }, onitemvisited: function(aitemid, avisitid, time) { emit(exports, "visited", bookmarkservice.ge...
... open "bookmarks.js" and replace its contents with this code: var { emit } = require("sdk/event/core"); var { eventtarget } = require("sdk/event/target"); var { class } = require("sdk/core/heritage"); var { merge } = require("sdk/util/object"); var {cc, ci} = require("chrome"); var { xpcomutils } = require("resource://gre/modules/xpcomutils.jsm"); var bookmarkservice = cc["@mozilla.org/browser/nav-bookmarks-service;1"] .getservice(ci.nsinavbookmarksservice); function createobserver(target) { var bookmarkobserver = { onitemadded: function(aitemid, afolder, aindex) { emit(target, "added", bookmarkservice.getbookmarkuri(aitemid).spec); }, onitemvisited: function(aitemid, avisitid, time) {...

JS XPCOM - Archive of obsolete content
xpcomutils - about protocol handler this example implements a quick about protocol handler in js using xpcomutils.jsm.
... components.utils.import("resource://gre/modules/services.jsm"); components.utils.import("resource://gre/modules/xpcomutils.jsm"); const cc = components.classes; const ci = components.interfaces; function abouthandler() {} abouthandler.prototype = { newchannel: function(uri) { var channel = services.io.newchannel("chrome://mystuff/content/mystuff.xul", null, null); channel.originaluri = uri; return channel; }, geturiflags: function(uri) { // do not return ci.nsiaboutmodule.uri_safe_for_untrusted_content unless // you make sure to set a non-system principal in newchannel.

How to convert an overlay extension to restartless - Archive of obsolete content
you should still be caching a reference to your string bundle on add-on startup, preferably using xpcomutils.jsm to lazily load the file.
... for example: components.utils.import("resource://gre/modules/services.jsm"); components.utils.import("resource://gre/modules/xpcomutils.jsm"); xpcomutils.definelazygetter(this, "strings", function() { return loadpropertiesfile("chrome://myaddon/locale/mystrings.properties"); }); function loadpropertiesfile(path) { /* hack: the string bundle cache is cleared on addon shutdown, however it doesn't appear to do so reliably.

Components.utils.import
for example, you can import xpcomutils.jsm to avoid copy/pasting long xpcom component registration boilerplate in your component files.
... example components.utils.import("resource://gre/modules/xpcomutils.jsm", this); difference from mozijssubscriptloader the differences from mozijssubscriptloader: the behavior when importing/loading the same code from different locations: the subscript loader evaluates the specified code each time it is invoked, with the caller's global object.

Miscellaneous - Archive of obsolete content
put this code in the components/certsservice.js file: const cc = components.classes; const ci = components.interfaces; components.utils.import("resource://gre/modules/xpcomutils.jsm"); const gobserver = cc['@mozilla.org/observer-service;1'].getservice(ci.nsiobserverservice); const gioservice = cc["@mozilla.org/network/io-service;1"].getservice(ci.nsiioservice); function certsservice() {} certsservice.prototype = { observe: function(asubject, atopic, adata) { switch(atopic) { case "app-startup": gobserver.addobserver(this,"xpcom-shut...

Tabbed browser - Archive of obsolete content
xul: <menuitem oncommand="myextension.foo(event)" onclick="checkformiddleclick(this, event)" label="click me"/> js: var myextension = { foo: function(event) { openuilink("http://www.example.com", event, false, true); } } opening a url in an on demand tab cu.import("resource://gre/modules/xpcomutils.jsm"); xpcomutils.definelazyservicegetter(this, "gsessionstore", "@mozilla.org/browser/sessionstore;1", "nsisessionstore"); // create new tab, but don't load the content.

How to implement a custom XUL query processor component - Archive of obsolete content
here is our sample javascript xpcom query processor: components.utils.import("resource://gre/modules/xpcomutils.jsm"); // basic wrapper for nsixultemplateresult function templateresult(adata) { this._data = adata; // just make a random number for the id this._id = math.random(100000).tostring(); } templateresult.prototype = { queryinterface: xpcomutils.generateqi([components.interfaces.nsixultemplateresult]), // private storage _data: null, // right now our results are flat lists, so no cont...

Providing Command-Line Options - Archive of obsolete content
b871-42cd-b33f-bfee4fcbf682} components/commandline.js contract @mozilla.org/commandlinehandler/general-startup;1?type=myapp {2991c315-b871-42cd-b33f-bfee4fcbf682} category command-line-handler m-myapp @mozilla.org/commandlinehandler/general-startup;1?type=myapp the javascript code const cc = components.classes; const ci = components.interfaces; components.utils.import("resource://gre/modules/xpcomutils.jsm"); components.utils.import("resource://gre/modules/services.jsm"); // changeme: to the chrome uri of your extension or application const chrome_uri = "chrome://myapp/content/"; /** * utility functions */ /** * opens a chrome window.

Creating a Login Manager storage module
const cc = components.classes; const ci = components.interfaces; components.utils.import("resource://gre/modules/xpcomutils.jsm"); function sampleloginmanagerstorage() {} sampleloginmanagerstorage.prototype = { classdescription: "sample nsiloginmanagerstorage implementation", contractid: "@example.com/login-manager/storage/sample;1", classid: components.id("{364a118c-747a-4f6d-ac63-2d2998e5a5c1}"), queryinterface: xpcomutils.generateqi([ci.nsiloginmanagerstorage]), // this registers the category for overriding...

How to implement a custom autocomplete search component
const ci = components.interfaces; const cu = components.utils; cu.import('resource://gre/modules/xpcomutils.jsm'); const class_id = components.id('x753d830-ba1e-11e0-962b-0800200c9a66'); // ← change this const class_name = "basic autocomplete"; const contract_id = '@mozilla.org/autocomplete/search;1?name=basic-autocomplete'; /** * @constructor * * @implements {nsiautocompleteresult} * * @param {string} searchstring * @param {number} searchresult * @param {number} defaultindex * @param {string} ...

JavaScript code modules
xpcomutils.jsm contains utilities for javascript components loaded by the js component loader.

Using the Places keywords API
using the keywords api the keywords api is a promise-based api available through the placesutils module: components.utils.import("resource://gre/modules/xpcomutils.jsm"); xpcomutils.definelazymodulegetter(this, "placesutils", "resource://gre/modules/placesutils.jsm"); setting a keyword for an url the insert() method accepts a keyword entry object describing the keyword to insert.