Debugging JavaScript (FBJS) in Facebook

I am developing an application on Facebook. I am running into some vague situation that I want to debug. The problem 开发者_如何学JAVAis that Facebook adds MUCH wrapping code and changes the name, not to mention that it already uses a modified version of JavaScript called FBJS. These things make it almost impossible to use tools like FireBug to debug the code. Does anybody have a suggestion for such cases? I am thinking of some debugging library that traces the code, variables, etc., and show me some results in some other window, or something like that.

You can try adding the line debugger to your javascript where you want to break. Firebug should break point on that line.