Matthew Eernisse at ONLamp.com - A Simpler Ajax Path:

"While not exactly new, the XMLHttpRequest object is receiving more attention lately as the linchpin in a new approach to web app development, most recently dubbed Ajax (asynchronous JavaScript and XML). [...] As it turns out, it's pretty easy to take advantage of the XMLHttpRequest object to make a web app act more like a desktop app--while still using traditional tools like web forms for collecting user input."