I'm right there with you in looking for solutions. As owner and lead developer for nitrotype.com (competitive real time online typing) and funtotype.com (soon there will be a real time scoreboard for competing).

At the moment we do all development in flash, not only because it allows for old IE support, but because I am able to salt+hash the scores sent to the server to verify the data but this is all done in flash.

In JS I'm stymied. Every scheme I can come up with I could easily defeat. No level of obfuscation is really that difficult to reverse. Hopefully somebody else has better input!