Can events fired from an iframe be handled by elements in its parent?

Question

Suppose I have a page located at www.example.com/foo, and it contains an <iframe> with src="http://www.example.com/bar". I want to be able to fire an event from /bar and have it be heard by /foo. Using the Prototype library, I've tried doing the following without success:

Element.fire(parent, 'ns:frob');

When I do this, in Firefox 3.5, I get the following error:

Node cannot be used in a document other than the one in which it was created" code: "4 Line 0

Not sure if that's related to my problem. Is there some security mechanism that's preventing scripts in /bar from kicking off events in /foo?

Answer 1

Events can be handled by a function defined the parent window if the iframe is a page from the same domain (see MDC's article on Same Origin Policy); however, events will not bubble up from the iframe to the parent page (at least not in my tests).

Answer 2

I haven't tested this cross-browser yet, but it works in FF.

In the iFrame you can fire on the element parent.document:

Event.observe(window, 'load', function() {
  parent.document.fire('custom:event');
});

and in the parent frame you can catch it with:

document.observe('custom:event', function(event) { alert('gotcha'); });