Professional ASP.NET 3.5 SP1 Edition: In C# and VB

Chapter 19. ASP.NET AJAX

AJAX is definitely the 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 it led to the creation of the AJAX model. AJAX applications, although they have been around for a few years, gained 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 and later renamed ASP.NET AJAX, makes it extremely simple to use AJAX features in your applications.

The ASP.NET AJAX toolkit was not part of the default .NET Framework 2.0 install. If you are using the .NET Framework 2.0, then it is an extra component that you must download from the Internet. If you are using ASP.NET 3.5, then you don't have to worry about installing the ASP.NET AJAX toolkit as everything you need is already in place for you.

Understanding the Need for AJAX

Today, when building an application, you have the option of creating a thick-client or a thin-client application. A thick-client application is typically ...