Use XML as a local data store Starting with the easiest part of your question first, what format do you use to store the data in? You mention XML files—and I would wholeheartedly agree with this.

What is AJAX (Asynchronous JavaScript and XML)? AJAX (Asynchronous JavaScript and XML) is a technique aimed at creating better and faster interactive web apps by combining several programming tools, ...

The key, said Antony Campitelli, formerly of Macromedia and now Laszlo's vice president of marketing, is finding a way to get around the twin problems of slow connections and often-overloaded servers.