For debugging and test on IE you need:

• IE7
• IE6 in a virtual machine (note that IE6 standalone has subtle differences from the real IE6 so it's not recommended)
• IE developer toolbar
• MSE7 debugger setup

Copy of notes from above site about MSE7

Microsoft Script Editor is probably one of the lesser known tools that can really make a difference when it comes to developing web applications. MSE is a debugger, much like Visual Studio and it comes bundled with Microsoft Office. It should not be mistaken for Microsoft Script Debugger which is a piece of crap compared to MSE. MSE got all the nice features Visual Studio has without the bloat.

MSE is installed at %ProgramFiles%/Microsoft Office/OFFICE11/MSE7.exe. Older versions might be installed at a slightly different location and if you cannot find it just search for mse. If you still cannot find it and you have an old Microsoft Office CD lying around you can install it from there. If you select custom install or add remove components it should be located under Microsoft Office / Office Tools / HTML Tools /Web Scripting / Web Debugging.

By default script debugging is disabled in IE but you can enable it by unchecking Tools / Internet Options... / Advanced / Disable script debugging (Internet Explorer).

So how do you use this mysterious tool? MSE allows you to debug exisiting IE processes but more importantly it is triggered by the debugger statement (which by the way also works if you have Venkman opened for Mozilla). If you already have IE up and running or you can’t edit the source files of the web application you can get into the debug mode by opening the Debug / Processes dialog and from there select the process to attach to.

Once in debug mode you can step through the program to see what is going on. Out of the box not much is shown but things like local variables, watch, running documents, call stack and more is available to you under Debug / Window.