Debug Javascript IE 9

I am using Visual Studio 2010 and IE 9. I am trying to debug javascript .js files in my Solution. I put the break point in the files and can't do it no matter what. I have tried doing things like unchecking options in IE like disable script debugging. And I can't do it no matter what.

Am I missing anything ?? I was able to debug javascript files yesterday and I am not able to do it today.

I pressed F12 AND Hit start debugger in developer tools of IE 9 and it gave me the message:

'Unable to attach to process. Another debugger might be atta开发者_如何学JAVAched to the process'

Any ideas and suggestions on what could be wrong.

When you hit F5 and Debug in Visual Studio it sometimes either doesn't attach the debugger to IE9 correctly, or normally in my case it just refreshes the app pool on a local running instance of Cassini (your Visual Studio Dev WebServer), which often if its already running will not let the VS Debugger attach correctly.

If you click in your system tray, find the icon for Cassini (ASP.NET Developement Server) - just right click and hit stop. Then go back to Visual Studio and F5 again, and the debugger should attach again ok.

My favorite thing to do is actually CTRL+F5 and run the web app without debugging so I can use the built in (F12) debugger in IE9. By doing that, you will not get the "Unable to attach to process..." message, and you will also be able to tell whether your Javascript edits are actually being refreshed or cached in your browser while you are developing.