deur Eric Uhrhane
This extension makes all html textareas into a very stripped-down version of Vi[m]. It's modal, supports infinite undo, has register support, search, visual mode, and various movement and editing commands. There's a lot yet to implement, but I've tried to cover all the basics that you'd use every day to type an email, edit a wiki page, etc. That being said, you'll note that the version number hasn't hit 1.0 yet.
If you like the power of ItsAllText, but want something a bit lighter-weight, give it a try.
This add-on is not compatible with your version of Firefox because of the following: