If they really want to
know JavaScript (in the Neo:
"I know Kung-Fu!" sense), then the IDE/Editor is of only secondary concern to actually
learning the language! There are many good books on JS, but the best one IMHO (if you only get one), is
JavaScript the Definitive Guide by David Flanagan. And guess what?
There is a brand new edition about to come out! (looks like May) It's going to cover all the new HTML5 hoopla.
Also recommended are:
[*]
DOM Scripting by Jeremy Keith.
[*]
JavaScript: The Good Parts by Douglas Crockford.
[*]
High Performance JavaScript by Nicholas C. Zakas
[*]
Bulletproof Ajax by Jeremy Keith.
[*]
JavaScript Patterns by Stoyan Stefanov.
[/list]
I really like Jeremy Keith's work in particular (very clear writing style) and "DOM scripting" is an excellent first book. It is a quick read which covers important best practices including the notions of
progressive enhancement and
graceful degradation. His follow-up "Bulletproof Ajax" extends these concepts to the world of Ajax as he presents his notion of "Hijax". (i.e. A site should work just fine even when Javascript is turned off.)
Regarding the IDE, I'm no expert, but I just use a plain old text editor (EditPadPro) and debug using Opera's built-in Dragonfly JavaScript debugger (which I prefer over FireBug). And of course, I always keep a copy of "The Definitive Guide" within arms reach!