I am currently working through a problem and at the point of pulling my hair out. I have an Ajax process that pops up a nice little div on success. In Firefox, predictably, I see the pop-up window and all is well. In IE, the ajax process runs and I do not get the pop-up window.
Maybe I am a little spoiled using Firebug because I can see the details of the request, the DOM and other important runtime bits. In IE I get nothing useful.
P.S. Any one who write 'The Microsoft Script Debugger' will be taken out back and shot.