Professional ASP.NET 2.0 Special Edition

Appendix C. Using Atlas

Ajax is a hot buzzword in the Web application world at the moment. Ajax is an acronym for Asynchronous JavaScript and XML and, in Web application development, it signifies the capability to build applications that make use of the XMLHttpRequest object.

The creation and the inclusion of the XMLHttpRequest object in JavaScript and the fact that most upper-level browsers support the use of this object led to creation of the Ajax model. Ajax applications, although they have been around for a few years, came to greater popularity after Google released a number of notable, Ajax-enabled applications such as Google Maps and Google Suggest. These applications demonstrated the value of Ajax.

Shortly thereafter, Microsoft released a beta for a new toolkit that enabled developers to incorporate Ajax features in their Web applications. This toolkit, code-named Atlas, makes it extremely simple to start using Ajax features in your applications today.

The Atlas toolkit is introduced as an appendix in this book because it is not part of the default .NET Framework 2.0 install. This is an extra component that requires an extra download from the Internet. Also, note that the code presented here is from the Atlas toolkit of April 2006 when it was still in its beta form.

Looking at the XmlHttpRequest Object

The support of the XmlHttpRequest object has given JavaScript functions the capability to call server-side events. Typical HTTP requests are usually issued by a browser. It is also ...