Please note that this is the same bug as reported in ticket 8779, which as since been closed, as the user found a workaround.

I'm raising this, as I'm not sure that this should not be fixed in the jQuery script, as it does not occur in most other browsers.

The issue I had:

1. Page with scripts that have $(document).ready() functions bound.

2. That page was being opened in a lightwindow.

3. On click of a button in the lightwindow, it was posting, and then on return, a script was running to close the lightwindow.

4. The error received is that 'jQuery' is undefined, from within one of my ready events. It seems that the document had been removed from the DOM prior to the event running.

After a bit more digging, it stems from this line (in the minified version):

function J(){return(new Date).getTime()}

which is called in the ready function - Date is undefined in IE9 at this point (as the document has been removed).

Now, I can workaround this by getting my lightwindow closing script to run in the jQuery(window).load() event - but this was a little hard to track down, and it may be of benefit to others if this failed gracefully in this scenario.

As mentioned in 8779, this applied to both 1.4.4 and 1.5.2.