chrome extension tabs.onUpdated analog for Firefox

I have some google chrome extension that uses tabs.onUpdated event (I need to be notified when the tab url is changed). Now I want to make the same extension for Firefo开发者_JAVA技巧x. But I cannot find the proper event. Does it exist or is there any other way to do it?

Take a look at Listening to events on all tabs, and some code samples here.