ASP.NET revolutionized Web application development. The platform handles many of the complexities of creating Web applications. Now ASP.NET AJAX takes the development platform even further. The lines between rich client applications and traditionally less interactive browser-based applications are being further blurred with the use of this technology.
The new server controls that are part of ASP.NET AJAX make it simple to designate parts of the page to be updated automatically without making the user pause and wait while the data is refreshed. You can have partial page updates without writing a single line of code. Other new controls let you alert the user that background work is happening and designate regular intervals at which updates occur. In addition, the ASP.NET AJAX Control Toolkit makes it easy to make your user interface really come to life with animations, modal dialogs, transition effects, and more.