AJAX server controls are rapidly growing in popularity. Like the ASP.NET server controls, they also can have methods and event handlers associated with them. The code for these methods and handlers is also processed on the server side. The two key differences between AJAX server controls and ASP.NET server controls are as follows:
AJAX server controls add script to the page which is run and processed within the browser. Some of the scripts may interact with the server in some way, but they are run on the client side. All ASP.NET server control processing is done on the server.
All AJAX server controls depend on one particular control to be present on the page for them to work at all. This is the
ScriptManager control, which we’ll discuss in a minute. ASP.NET server controls have no such reliance.
AJAX server controls also offer the same consistent programming model as ASP.NET server controls. Those controls formerly in the ASP.NET AJAX Extensions 1.0 download are now integrated into VS2008 and are accessed with the same syntax as ASP.NET server controls.
<asp:controlType id="ControlID" runat="server" thisProperty="this value" thatProperty="that value"/>
In addition to the core AJAX server controls included with VS2008, Microsoft also leads a community project to build a set of useful AJAX server controls, called the AJAX Control Toolkit. You can find it online at http://www.codeplex.com/ajaxcontroltoolkit. Appendix A covers its installation.
If you want to add controls ...