XML.com: Errors and AJAX

XML.com: Errors and AJAX: "Errors and AJAX
by Joshua Gitlin
May 11, 2005

In case you haven't heard by now, the hottest buzzword in the realm of web technology is AJAX (as coined in an Adaptive Path essay). The crux of the AJAX framework is the XMLHttpRequest JavaScript object which allows client-side developers to send and receive XML documents over HTTP without interrupting the user, and without hacking around with hidden frames. Now, some might shudder at the notion of allowing client-side developers who might be more used to validating forms and animating rollover images to suddenly be responsible for traversing XML documents and negotiating HTTP headers, but without risk, there is no reward. And just to soothe any lingering trepidation, I will demonstrate how to use XMLHttpRequest to not only add previously impossible or infeasible features, but also to reduce errors and improve quality."

An old article as far as AJAX goes - but still VERY relevant.