Working with JQuery in Visual Studio, we don't have all the nice navigation, refactoring, and immediate error visibility we have with C# and ReSharper.  Today I installed RubyMine, a brand new IDE from JetBrains.  I opened up a javascript file and was pleased to find that the ReSharper/IntelliJ IDEA experience transfers over one-to-one.  All the shortcut keys are the same and all the refactoring and navigation was here, too.  It makes working with Javascript a breeze!  This IDE is brand-new, and I hope that they will plop this functionality into ReSharper for Visual Studio users, but for now, this is a good workaround when dealing with some non-trivial Javascript.  In this screen-shot below, you can see that I pressed CTRL+SHIFT+F7 to show usages of "this._jqm".  It highlights all the usages, just like with ReSharper

I then tested out the refactoring and extracted a variable with CTRL+ALT+V.  The following dialog was to be expected, and it refactored just like I'm used to with C#.

This is a very interesting IDE, and I'll be keeping tabs on it.  It is focused for Ruby development, but it can be useful apart from a server-side framework.