Javascript - Visual Event

This is a very handy tool for getting information on what event handlers are attached to what elements on a webpage. Something like this should be integrated into Firebug and / or WebKit developer tools:

Visual Event is an open source Javascript bookmarklet which provides debugging information about events that have been attached to DOM elements. Visual Event shows:

Which elements have events attached to them
The type of events attached to an element
The code that will be run with the event is triggered
The source file and line number for where the attached function was defined (Webkit browsers and Opera only)