ASP.NET AJAX, formerly code-named Atlas, is a set of extensions to ASP.NET developed by Microsoft for implementing Ajax functionality.

Including both client-side and server-side components, ASP.NET AJAX allows the developer to create web applications in ASP.NET 2.0 (and to a limited extent in other environments) which can update data on the web page without a complete reload of the page. The key technology which enables this functionality is the XMLHttpRequest object, along with Javascript and DHTML.

ASP.NET AJAX was released as a standalone extension to ASP.NET in January 2007 after a lengthy period of beta-testing. It was subsequently included with version 3.5 of the .NET Framework, which was released alongside Visual Studio 2008 in November 2007.

After an Ajax request, the HTML within some portions of the page (for ASP.NET Ajax this is the "update panel") are being completely re-rendered with new HTML and therefore it's impossible to keep client side state across Ajax Server Side event handlers. This can be seen by the fact that the Auto Completer in the ASP.NET Ajax Control library (which is an extension to ASP.NET Ajax) has to use WebServices to retrieve data instead of the far more intuitive way which would have been to use a server side event handler embedded as a method into the page the control resides within.

Name change and road map

On 11 September 2006, Scott Guthrie, General Manager in charge of the .NET platform at that time, announced that ATLAS would be renamed and launched as three products towards the end of the year.^[1] The new products were to be called the Microsoft AJAX Library, containing the front end JavaScript library, the ASP.NET 2.0 AJAX Extensions, containing the server-side .NET code, and ASP.NET AJAX Control Toolkit, containing shared source controls that could be used to "get the most value from the ASP.NET AJAX Extensions".

A major change since its inception includes the change of the root namespace from "Microsoft.Web" to "System.Web".^[2]

The production version was released on 23 January 2007.^[3]

Microsoft AJAX Library

The Microsoft AJAX Library is a standalone collection of the standards-based JavaScript classes included in ASP.NET AJAX. It is supported by most popular browsers and can be used to build client-centric web applications that integrate with any backend data provider. Ajax, shorthand for Asynchronous JavaScript and XML, is a web development technique for creating interactive web applications.

Browser support

ASP.NET AJAX supports multiple modern web browsers such as Internet Explorer, Firefox, Opera and Safari.^[4] Mobile devices such as Windows Mobile are currently not supported.

See also

• Ajax framework
• Ajax.NET
• ASP.NET

References

External links

• ASP.NET AJAX (formerly "Atlas")
• Atlas At Last : ASP.NET Atlas Powers the AJAX-Style Sites You’ve Been Waiting For
• Microsoft Atlas Mini-Guide from SearchVB.com - Registration Required
• Ajax Tools for ASP.NET Developers
• ASP.NET AJAX Articles selection
• AJAX Control Toolkit