Just FYI, all over the web are recommendations to debug IE with Microsoft Script Editor.
In case you don't have it installed and don't have an Office Install CD handy, you can download the Visual Web Developer 2005 Express Edition for free and it will handle debugging. It's weird to use, I think you have to create a Web Site project and import copies of your javascript to set breakpoints even though you are running off of a remote server. But in the end it works, and it helped me find a single extra comma in an object declaration that prevented my whole app from running in IE. Just FYI.
