A feature rich JavaScript IDE environment?

Question

I'm currently using Visual Studio 2008 to edit .js files with, and it has decent support but I want more...

I like the VS syntax highlighting and auto-indentation features but additionally would like advanced features like: contextual info and help, collapsible JavaScript blocks, implicit symbol understanding for searching, refactoring and that kind of thing; also warnings and errors for the js code.

Suggestions?

Edit: ooops... for the Windows platform. I see some Eclipse answers already and that's fine as I'll install Eclipse on Windows.

Purpose: I want the tool to be feature rich to aid my understanding of what's happening because JavaScript can get quite obtuse when jQuery is being used. Actually, it can be quite obtuse to understand regardless. Plus the additional (non-jQuery) branching for different browsers and tweaks. It can take a long time to wade through.

Answer 1

I use Komodo Edit or Aptana