I still can't belive this is not possible but is there a way to loop through the dom and see all event handlers attached using 'addEventListener'. This post and many others says no.
If that's the case then how do apps like Chrome's inspector or Firebug show them, which they do? I guess they probably augment the dom's methods in some way so they can track what's being bound.
Of course browsers internally have a list of event listeners, but it is not exposed to page-level JavaScript. For example, Firebug (or Eventbug) probably use nsIEventListenerInfo.
That being said, this old answer still holds:
How to find event listeners on a DOM node?