First off, Sencha Designer 2 just came out (beta) and will support graphical layout plus code editing. U shud try that. Or consider eclipse plus the spkt exten

First off, Sencha Designer 2 just came out (beta) and will support graphical layout plus code editing. U shud try that. Or consider eclipse plus the spkt extension, which offer code completion for extjs. If you aren't using sencha stuff, then ms visual studio has pretty good javascript support. Use firefox w firebug, and try jasmine for unit testing