Asp.net is a web application framework. It is being build and designed by Microsoft. The application of asp.net is to build dynamic websites, web applications and web services. It is the successor of active server pages technology of Microsoft. This helps developers to build customized applications for customers. Asp.net is built on common language runtime which helps developers to write codes of asp.net by using supportive languages of .net framework. It was first introduced in the year of 2002. The web pages of asp.net are officially known as web forms. Over asp the benefits are high in asp.net for developers. They can build pages composed of controls as the way it happens in windows user interface.

Asp.net has extensions framework for it, these are developed by Microsoft so as to increase the functionality of asp.net. The extensions are asp.net Ajax and asp.net MVC framework. With the support of asp.net developers can build and design customized applications for customers. Developers can offer different services based on this to customers. Developers can design and program applications through asp.net, Integration of work can be done to Java and asp.net, Web services can be developed through asp.net. Hence asp.net has lot of features which is very much helpful for software developers. This can really help software developers to build dynamic applications for the customers and as per the need. Even migration can also take care through asp.net. For eg: from web based and standalone applications to .net framework applications.
Asp.net has lot of advantages which can really increase the performance of the applications. The advantages like High speed development, Productivity, and even this is highly secured. Even the performance benefits are there over the script based languages. Asp.net is better than asp in performance benefits. It compiles the server side code to one or more DLL files on the web server. This feature helps to develop applications easily offered by the scripting languages. It has improved run time error handling over classic asp.

Asp.net uses multi language abilities of, net as it runs on common language runtime. It helps the developers to code with the help of other .net framework languages such as VB.Net, C#, Delphi.net, etc.

Hence asp.net is very much helpful and supportive web application framework where software developers can provide customized applications and solutions in .Net and Ajax and even windows application developments. The asp.net framework has performance benefits over classic asp. It has the similarities in terms of controls and events with Microsoft windows applications. Asp.net is a good and supportive framework for web application frameworks.

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Reference: wiki and http://www.summationit.com/asp.php