Intercepting Page Loads - Archive of obsolete content
here's a code sample that keeps track of your progress listeners for all tabs: init : function() { gbrowser.browsers.foreach(function (browser) { this._toggleprogresslistener(browser.webprogress, true); }, this); gbrowser.tabcontainer.addeventlistener("tabopen", this, false); gbrowser.tabcontainer.addeventlistener("tabclose", this, false); }, uninit : function() { gbrowser.browsers.foreach(function (browser) { this ._toggleprogresslistener(browser.webprogress, false); }, this); gbrowser.tabcontainer.removeeventlistener("tabopen", this, false); gbrowser.tabcontainer.removeeventlistener("tabclose", this, false); }, handleevent : function(aevent) { let tab = aevent.target; let webprogress = gbrowser.

Tabbed browser - Archive of obsolete content
at's been moved } function exampletabremoved(event) { var browser = gbrowser.getbrowserfortab(event.target); // browser is the xul element of the browser that's been removed } // during initialization var container = gbrowser.tabcontainer; container.addeventlistener("tabopen", exampletabadded, false); container.addeventlistener("tabmove", exampletabmoved, false); container.addeventlistener("tabclose", exampletabremoved, false); // when no longer needed container.removeeventlistener("tabopen", exampletabadded, false); container.removeeventlistener("tabmove", exampletabmoved, false); container.removeeventlistener("tabclose", exampletabremoved, false); note: starting in gecko 1.9.1, there's an easy way to listen on progress events on all tabs.

Event reference
tabclose addons specific a tab has been closed.