I recently put together a third example for the SAJAX project (http://www.modernmethod.com/sajax/); this one uses the concept behind Google Suggest, which is to populate an HTML input box with an array coming from the server.
Very useful if you have lots of input boxes on a page, each which you want to have a different set of autocomplete data.
The code could be extended to work just like Google Suggest; the hard part was figuring out how to get the array passed back intact. I tested it with >5000 items in the array, and it worked seamlessly.
The code is at:
It doesn’t seem to be working in FireFox at the moment. But, if I get some time this weekend I’ll try and look into that.