While testing a client’s Joomla! 1.5 site with various browsers, recently, I got the following error when testing with Internet Explorer 6.

Internet Explorer cannot open the Internet site http://www.example.com/index.php.

Operation aborted.

This was puzzling, as we had successfully tested the site before with IE6.  IE7 and IE8 were working fine.  A little checking of the recent changes revealed that SEF URLs had been enabled.  Turning off this feature made the error go away.  Some research turned up a blog post describing the error on the official IE blog.  The short answer is that a bit of JavaScript was trying to modify an element in the document before it had been completely parsed.  While that made sense, there is a lot of JavaScript in a stock Joomla! installation, and this particular installation was using even more.

After a lot of searching, I discovered the culprit: FB.Share.  This is a JavaScript library from Facebook that allows one to create a Facebook share button on one’s site.  I didn’t bother digging into the JavaScript to see exactly what the problem was and why it only happened when SEF URLs are turned on.  Due to a prior change, we weren’t using it any longer and had just forgotten to delete it.  Once I removed the link:

<script src="http://static.ak.fbcdn.net/connect.php/js/FB.Share" type="text/javascript"></script>

the site started working again.