The Microsoft's goal at this point is to develop a series of small libraries that a browser can load into memory as necessary -- rather than loading one huge library -- that will give Web developers the framework for implementing on-page controls. These controls provide animated functionality, and more importantly, can be loaded with variable amounts of new content as necessary by resuming HTTP contact with the Web server; thus, the "asynchronous" aspect of the language.
The way AJAX (from Microsoft, Google and others) could fundamentally change the nature of Web site design is by enabling, for the first time, a Web site's entire content, regardless of size or breadth, to be delivered through a single page. The entire page would not need to be loaded into the browser beforehand; instead, the browser simply collects resources and data from the server as the user requests them. For at least some sites, the entire notion of "page hierarchy" could end here.
Microsoft's AJAX differs from its original attempt at Web-based functionality distribution, ActiveX (the original "A" in "ASP.NET") in many important respects. First of all, it is browser independent, although its relative performance in Firefox, Safari and other browsers will require continued scrutiny. Second, it does not rely on functions tied to the core of the operating system, the way ActiveX relied on the Component Object Model. As a result, the already vulnerable OS isn't pried open to attack even further.
Third, there's some buzz behind AJAX that ActiveX never had, partly because Microsoft's not the only player in this arena - in fact, it's a minority player that's coming from behind. This time, it's Microsoft that's pushing for a level and competitive playing field, which wasn't the case back when Netscape fought to keep up with Microsoft's ever-changing definitions and requirements for ActiveX.
The first baby steps Microsoft took into the waters of AJAX came last year with the release of the "Atlas" Community Technology Preview, which was based mostly on a single library. Since that time, the company has decided that the functionality set for AJAX 1.0 will be more limited than in the CTP, although certain controls and features that 1.0 will exclude, will continue to be supported by the CTP.
As a result, AJAX 1.0 Beta 1 and AJAX 1.0 CTP are now separate libraries; and in a manner fitting for Microsoft, the sample AJAX program toolkit also released today actually requires both libraries to be installed, and may continue to do so.
Previously posted at blog.Solidsoft.com