<p>I can't seem to get Javascript debugging working for my ASP.NET MVC application even though I can for a traditional ASP.NET WebForm app.</p>

<p>I have followed the steps for unchecking the 'Disable Script Debugging' boxes for both IE and other.</p>

<p>when I add a simple function to display an alert in both the site.master and any content view the breakpoint will not fire.</p>

<p>Have i missed something obvious or do I need to use an outside tool for debugging like FireBug?</p>

<p>By the way, I'm using Visual Studio Web Developer Express 2008.</p>

<p>thx</p>

I don't use VS.Net Express, but in VS.Net Standard you can go to the Debug menu in your solution and choose "Attach to process". You will then get to choose the debug type: Native, Managed, or Script. Select Script, then select your process from the list. A list of scripts will now come up in your IDE. Click on script one you want to debug, throw in a breakpoint or two, and you should be ready to go.
If MS has nerfed the Express version so that you can't attach to a process, then I guess you're stuck and will need the $$$ upgrade (which wouldn't entirely surprise me). Hey, what do you want for free? :)