ASP.NET is a set of web development technologies created by Microsoft. It can be used to create web sites, web applications and XML web services. It is part of Microsoft’s .NET platform and is the next generation of Microsoft old ASP(Active Server Pages) technology. Even though they share similar names, ASP and ASP.NET are vastly different. ASP is mostly written in VBScript, while ASP.NET is mostly based upon Microsoft’s CLR (Common Language Runtime) technology, which is very much similar to Sun Microsystem’s Java Virtual Machine. ASP.NET code can be written in all of the .NET platform languages, such as C#, Visual Basic.NET, and also other open source languages such as Perl and Python.

ASP.NET is different from other web development languages in that it encourages the programmer to develop applications using an event-driven GUI system, rather than in other web-scripting environments like PHP. ASP.NET has a number of advantages over other forms of web development. Its code are compiled, meaning that applications can run faster with more design-time errors trapped at the development stage. It also has significantly better error handling and catching.