Catching events from Iframe in Firefox

Question

This should subscribe function "handler" on scroll events from every iframe on the page

var iframes = document.getElementsByTagName("iframe");
for (i = 0; i < iframes.length; i++) {
  var current = getRealObject(iframes[i])
  current.contentDocument.addEventListener('DOMMouseScroll', handler, false)      
}

function getRealObject(object) {  // unwraps the object if necessary
  return (object.wrappedJSObject) ? object.wrappedJSObject : object
}

... but on some pages it doesnt. Furthermore, in those cases anything in contentDocument is inaccessible, and without unwrapping contentDocument is null. Using FF 3.5

UPD iframe content and page are from the same domain

Answer 1

If the page in the iframe is from a different domain that the page containing the iframe, then you do not have access to the DOM of the iframe. This is a security feature.