I’m using script.aculo.us 1.7.1 beta 3 with prototype 1.5.1.1, and I’ve found a bug when I use draggables in Internet Explorer. If I modify the DOM tree and then try to drag an object, I get an “Unspecified Error” at line 3088 (in prototype.js version 1.5.1.1).

This works fine on other browsers like Firefox and Opera. I think the problem is that IE doesn’t return null.

After searching for a solution, I came across this post (http://forums.asp.net/p/1038609/1444564.aspx) which suggests wrapping the offsetParent code in a try…catch block. So I tried it and my code now works in IE. Woohoo!!!

  cumulativeOffset: function(element) {
    var valueT = 0, valueL = 0;
    try {
        do {
          valueT += element.offsetTop  || 0;
          valueL += element.offsetLeft || 0;
          element = element.offsetParent;
        } while (element);
    }
    catch( ex ) {
    }
    return [valueL, valueT];
  },

I’m not sure if this is the best solution, but it seems like the simplest.

Here’s a fix to allow PNG transparencies in IE 5.5 and 6. This is a CSS-based solution so it doesn’t conflict with JavaScript like some other solutions.
http://www.twinhelix.com/css/iepngfix/

This page has a better explanation of how to use it:
http://bjorkoy.com/past/2007/4/8/the_easiest_way_to_png/

Also, here’s a good test page, but I don’t recommend their JavaScript solution:
http://homepage.ntlworld.com/bobosola/pngtest.htm

For info from Microsoft on this problem, see this page:
http://support.microsoft.com/kb/294714