is there any javascript out there that will let you track which advertisers are clicked on within the ad units?
I think you can track your clicks with google analytics account. There are some methods how to track clicks using google analytics
But NOT what ads are being clicked on. This can no longer be done via any method ever since Google changed the code.
I actually did find one thing, but it's only available for Mint (out of the box). http://www.digitalmediaminute.com/article/1715/adsense-click-pepper
yeah it is kind of old, but how knows, it might still work. I'm going to give it a try sometime soon.
Let us know...I'd be surprised, though, the feature that it uses to get the ad url was disabled by Google. And because of security settings in Firefox and the new IE it was already a problem before Google put the final nail into the coffin. But, you never know, give it a shot.