Q: how to trace or debug javascript closures in firebug How do i trace the values of local variables in closure, and also the execution flow of closures in firebug. or is there any other tools that is specifically for debugging closures.

A: Yes. You can debug the javascript closure with Firebug.  On Script tab, you can see all the object instances as well as the state of the whole object. Please, Find it below the screenshot of firebug showing local variables in closure.

(source: pengbos.com) 
If you want to learn more read this here  and practice it.

A: In Google Chrome's Developer Tools you can inspect the closure stack by setting a breakpoint (in the Scope Variables section):

I would assume Firebug has similar functionality.

A: You can see Closure Inspector of Firebug.
