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#4469 closed bug (worksforme)

Opened April 01, 2009 10:08PM UTC

Closed November 19, 2010 10:17PM UTC

Last modified March 13, 2012 05:00PM UTC

Event: hover does not trigger properly when scroll bars are present

Reported by: sairex Owned by:
Priority: major Milestone: 1.4
Component: event Version: 1.3.2
Keywords: Cc:
Blocked by: Blocking:

Hover does not properly trigger on/off when its parent container has an overflow: scroll/auto property set to it.

For example:

Modify the example so that the UL has the CSS property overflow: auto; height: 30px;

Now go over each LI element back and forth over the scrollbar. The LI hover event will not trigger, only the UL hover event triggers.

Attachments (1)
Change History (7)

Changed May 15, 2009 10:36AM UTC by bfg comment:1

It seems to be only Firefox bug, confirmed jQuery 1.2.6+

Changed September 18, 2009 02:18AM UTC by emparq comment:2

I ran into the same problem:

1. set up a mouse event-handler for a div with 'overflow:scroll'

2. mouse over the scrollbar (I'm on Firefox 3.0.14, Fedora 10, x86_64)

3. Firefox throws a 'permission denied to XULElement.parentNode' error

4. remaining code is not executed

The main issue seems to be that the scrollbar widget (scrollbar + scroll-up/down buttons) are of native XULElement-type in Firefox, and trying to access a property of an object of this type is a no-no (even inside a try-catch block, it seems).

Thanks to the ExtJS-folks though (thanks Condor and mystic), there's a work-around (see, which fixes the described problem behavior (for me at least).

Here's the verbose code (old code commented out, alternate code w/ original comments inlined):

var withinElement = function(event) {
  // Check if mouse(over|out) are still within the same parent element
  var parent = event.relatedTarget;
  // Traverse up the tree
  while ( parent && parent != this )

    // permission denied error if 'parent' is of XULElement-type (which
    // will happen when mousing over the scrollbar-widget in FF)
    try { parent = parent.parentNode; }

//  alternate solution:
    try {
      // Prevent "Permission denied to get property XXX"-type
      // errors in Firefox when mousing over
      // 1) XULElements (e.g. scrollbars, scrollbar buttons etc)
      // 2) anonymous <DIV>s (i.e. <div class="anonymous-div">) contained in
      //    <INPUT> elements
      // See for more info
      // tested successfully on:
      //  -- Fx + FB 1.3.1
      //  -- Fx 3.0.12 / 3.5.1 + FB 1.4.1
      //  -- Fx 3.0.14 (Fedora 10, + FB 1.4.2
      var s =;
      if (s == '[xpconnect wrapped native prototype]' || // FF 3.5 check
          s == '[object XULElement]') {                  // FF < 3.5 check
      parent = parent.parentNode;

    catch(e) { parent = this; }

  if( parent != this ){
    // set the correct event type
    event.type =;
    // handle event if we actually just moused on to a non sub-element
    jQuery.event.handle.apply( this, arguments );

Changed November 17, 2009 12:35PM UTC by thorn comment:3

emparq, thanks for mentioning this workaround. But it didn't work for me until I replaced 'return' with 'break'.

Changed January 09, 2010 06:03PM UTC by pkh80 comment:4

Does applying this workaround require using the non-minified version of jquery? Can someone post a brief explanation of using the patch?


Changed June 12, 2010 02:24PM UTC by dmethvin comment:5

component: unfiledevent

Changed November 19, 2010 10:17PM UTC by snover comment:6

resolution: → worksforme
status: newclosed

This doesn’t appear to be an issue in current versions of Firefox + jQuery; please reopen if this is not the case.

Changed November 19, 2010 10:18PM UTC by snover comment:7

#5631 is a duplicate of this ticket.