This is an archived page. It's not actively maintained.



Support for extensions using XUL/XPCOM or the Add-on SDK was removed in Firefox 57, released November 2017. As there is no supported version of Firefox enabling these technologies, this page will be removed by December 2020.

Add-ons using the techniques described in this document are considered a legacy technology in Firefox. Don't use these techniques to develop new add-ons. Use WebExtensions instead. If you maintain an add-on which uses the techniques described here, consider migrating it to use WebExtensions.

Starting from Firefox 53, no new legacy add-ons will be accepted on (AMO) for desktop Firefox and Firefox for Android.

Starting from Firefox 57, only extensions developed using WebExtensions APIs will be supported on Desktop Firefox and Firefox for Android.

Even before Firefox 57, changes coming up in the Firefox platform will break many legacy extensions. These changes include multiprocess Firefox (e10s), sandboxing, and multiple content processes. Legacy extensions that are affected by these changes should migrate to use WebExtensions APIs if they can. See the "Compatibility Milestones" document for more information.

A wiki page containing resources, migration paths, office hours, and more, is available to help developers transition to the new technologies.



Helper functions for working with favicons.



getFavicon(object, callback)

Takes an object that represents a page's URL and returns a promise that resolves with the favicon URL for that page. The object can be a URL String or a Tab. The platform service (mozIAsyncFavicons) retrieves favicon data stored from previously visited sites, and as such, will only return favicon URLs for visited sites.

let { getFavicon } = require("sdk/places/favicon");

// String example
getFavicon("").then(function (url) {
  console.log(url); //

// Tab example
  url: "",
  onReady: function (tab) {
    getFavicon(tab).then(function (url) {
      console.log(url); //

// An optional callback can be provided to handle
// the promise's resolve and reject states
getFavicon("", function (url) {
  console.log(url); //

object : string|tab
A value that represents the URL of the page to get the favicon URL from. Can be a URL String or a Tab.

callback : function
An optional callback function that will be used in both resolve and reject cases.


promise : A promise that resolves with the favicon URL.