Another AJAX framework with a little more meat to it.
I JUST got comfortable with moo.ajax and another framework comes along. :-)
AdvancedAJAX 1.0 is a little more heftier (10k) than the moo.ajax framework, but I believe AdvancedAJAX does a little bit more and seems like a more complete solution.
It allows for a username and password combination, a separate page for success and for failure, custom HTTP headers and retry delays and durations.
...and that was just scratching the surface. There are a ton of events for each AJAX request. Check it out for yourself and see if this handles your AJAX needs. It does mine.
(BTW, the download option is on the far right. It took me a while to find it.)