How to debug firefox plugin?

Question

I'm writing plugin for firefox and I need a way to debug it. Plugin written in javascript. So is there is a elegant way how I can debug it?

Update 2014: There's a builtin Firefox debugger

Answer 1

Chromebug is a useful tool which allows JavaScript debugging and inspecting XUL elements. You can take a look at a few screenshots here.

Answer 2

The Mozilla Developer Center has plenty of useful information on this topic (as well as many others).

I would recommend Setting up an extension development environment as a good place to start.

Answer 3

You can use Firebug or Venkman's Javascript Debugger.