Beginning Web Development, Silverlight, and ASP.NET AJAX

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CHAPTER 12 ■ AJAX EXTENSIONS FOR ASP.NET
to carefully tweak exactly which parts of your page you’ll want to have updated when you
do a partial page refresh.
With these and many more potential scenarios in mind, ASP.NET AJAX has been
designed to provide controls, script libraries, and technology support to make building
RIA applications as easy for the developer as possible.
The functionality of ASP.NET AJAX has been broken down into two paradigms: server,
containing the suite of ASP.NET controls to handle things such as partial refreshes,
update progress, timers, and server-side integration with other applications across web
services or other communications profiles; and client, which contains JavaScript classes
to support value-added functionality, such as a browser-independent layer, extensions to
support object orientation, and more.
You can see the basic ASP.NET AJAX server and client architectures in Figure 12-1.
Figure 12-1. ASP.NET AJAX client and server architectures
The ASP.NET infrastructure provides many application services to server applications,
including components that manage the UI and flow of an application (see Part 1 of
this book for more details), handling serialization, validation, and extensibility, among
other things. ASP.NET 2.0 also supports services such as database-backed user profiles
and security and authentication methodologies. When using ASP.NET AJAX extensions,
the whole ASP.NET framework is available for you to use, providing many value-added
services, saving you time and effort in development.
ASP.NET also supports and provides web services that can be called from a client
script that can work with the resources that ASP.NET provides. For example, you can use
client scripts to help protect resources through forms authentication, or you can access
user profiles, allowing user-specific settings to be stored on the server.