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.

The BrowserApp object is only available to privileged code running on Firefox for Android, and is intended for use by Firefox for Android add-ons.


BrowserApp.getTabForId() retrieves a browser tab, given its unique ID.


var tab = window.getTabForId(id);

The tab's unique ID, which can be found as the id property of the Tab object.


tab: the Tab corresponding to this ID.


This function returns the title of the document hosted by a tab, given the tab's ID:

function tabTitle(id) {
  let tab = window.BrowserApp.getTabForId(id);
  return tab.window.document.title;

See Also

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