Nice, fun to see whats possible with a bit of "trickery"
To add to this, my usual method of implementing anything ajax is to go as simple as possible - no external libs (i.e. prototype and yahoo ui), but a very simple 3 function javascript file (which grows easily).
The link that got me started was this. It's from the php mailing list from rasmus (fellow who developed php). Not saying its always the best method, but I was running into things where I wanted to do something quick and simple, and I had no desire to include the entire prototype or yui libs.
That's a nice little site. Very cool for people who don't want to load huge libraries. Personally I like JQuery the best. It seems to make the most sense as far as a javascript/ajax library goes.
