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.
From Firefox 53 onwards, no new legacy add-ons will be accepted on addons.mozilla.org (AMO).
From Firefox 57 onwards, WebExtensions will be the only supported extension type, and Firefox will not load other types.
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 WebExtensions if they can. See the "Compatibility Milestones" document for more.
A wiki page containing resources, migration paths, office hours, and more, is available to help developers transition to the new technologies.
Unstable
Helper functions for working with favicons.
Globals
Functions
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("http://mozilla.org").then(function (url) {
console.log(url); // http://mozorg.cdn.mozilla.net/media/img/favicon.ico
});
// Tab example
require("sdk/tabs").open({
url: "http://mozilla.org",
onReady: function (tab) {
getFavicon(tab).then(function (url) {
console.log(url); // http://mozorg.cdn.mozilla.net/media/img/favicon.ico
});
}
});
// An optional callback can be provided to handle
// the promise's resolve and reject states
getFavicon("http://mozilla.org", function (url) {
console.log(url); // http://mozorg.cdn.mozilla.net/media/img/favicon.ico
});
Parameters
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.
Returns
promise : A promise that resolves with the favicon URL.