The closest I've found to an interactive forum like UT is www.alistapart.com, but the users are more designers than programmers, and focus more on CSS than JS, but still JS discussion. A neat site in itself.

Not sure precisely what resources you're looking for, but here are some that I've found in my searching.

Places to start

www.Netscape.com -- in Browser Central, you'll find the language definition for all versions, some sample code, and a 'browser sniffer' which is important for agent detection. You may need to DL NS 6 in order to access all of the site!

www.msdn.microsoft.com/scripting/default.htm offers its language def of JScript, and sample code. Be sure to pick up the Script Debugger if you're working in IE. Like much web stuff, JS is "forgiving" when it comes to incorrect code. That means it fails without giving any feedback. The debugger flags and identifies problems.

Online Tutorials and FAQs

Here are a couple other sites I've found helpful. At these and similar sites, you should be able to find overall information as well as specific scripts.

http://www.javascriptdatabase.com/
http://www.irt.org/

Games

If you're interested in more significant efforts in JS, games illustrate a lot of language features. Here are a couple sites:

http://www.javascript-games.org/

http://www.the5k.org/ -- is the result of a just-completed contest -- creating a web page in less than 5K. There's a lot of stuff in JS. Much of the code, for performance and size reasons, is hard to read (a lot of 1 line programs!), but nothing a simple reformat can't help. You'll find 3D rendering engines, fractal generators, and some other pretty amazing stuff.

Integration with other technologies

JS is a "supporting" technology of HTML and integrates with the DOM, CSS, and other technologies. There are a variety of places for the interrelationship, the following is one I've found helpful:

http://www.w3schools.com/

The W3 standards org has established standards for a variety of these technologies, see:
http://www.w3.org/

Books helpful:

JavaScript: The Definitive Guide, Flanagan, published by O'Reilly. Even though it only covers to v 1.2, still the best overview of the language. (NS 6 uses 1.5, IE 5 uses 1.3).

JavaScript Bible, 4th edition, Goodman, published by Hungry Minds. Covers current crop of browsers, more oriented towards web development, excellent list of features by version.

Enjoy!

Jay