Build highly responsive and interactive Ajax-enabled Web applications.
EditBy: The Ajax Control Toolkit contains controls that you can use to build highly responsive and interactive Ajax-enabled Web applications. These controls do not require knowledge of JavaScript or Ajax. They are designed using concepts that are familiar to ASP.NET Web Forms application developers. Using the Ajax Control Toolkit, you can build Ajax-enabled ASP.NET Web Forms applications and ASP.NET MVC Web applications by dragging the controls from the Visual Studio Toolbox onto a page. The Ajax Control Toolkit is an open-source project that is part of the CodePlex Foundation.

Whats new:
This is a refresh release that fixes some of the issues discovered in the 1.0.10606.0 release.
It has two flavors that work against two versions of the .NET Framework:
路 ASP.NET AJAX version 1.0 and .NET Framework 2.0
路 .NET Framework 3.5 Beta

General fixes:
路 Tabs: Resolved NamingContainer issues so that FindControl works as expected in Tabs.
路 ToolkitScriptManager: Shorter combined script URLs and new HTTP handler support for generation of combined script files.
路 Dependencies: Removed explicit reference to VsWebSite.Interop.dll and stdole.dll. They will not be automatically included in the web configuration files by Visual Studio.
路 FilteredTextBox: Navigation, Control and Delete keys work fine in all browsers.
路 Localization: Turkish, Dutch, and Traditional and Simplified Chinese language support added. you can free download AJAX Control Toolkit 1.0.10618.0 now.