ASP.NET improves on the type of application that developers could utilize in classic ASP, and adds a new application, called a webservice.

In classic ASP, there was in reality only one type of application—one in which a client accessed a page with the .asp extension and in which that page, either through fixed VBScript or JScript or through script in combination with components built on Microsoft’s COM standard, returned HTML to the browser to form the user interface with which the client would work together. Clients typically interacted with the application only through this user interface and did not have the alternative of creating their own option interface to the functionality exposed by the application.

ASP.NET provides an improved version of this type of application. ASP.NET also introduces a new type of application, called a webservice, which provides clients the capability to use functionality exposed by an application without being attached into that application’s user interface implementation.

The ASP.NET Web Application is the type of application most developers will effort with on a regular basis. The terminology comes from the description used in the Visual Studio .NET environment to explain the project type used to create this type of application. You may also listen to this type of application described as an ASP.NET Web Forms Application.

An ASP.NET Web Application, in its simplest form, consists of a directory set available via HTTP using the IIS administration tool and at least one ASP.NET page, designated by the .aspx file extension. This HTML and server-side code combine to generate the final output of the page, typically consisting of HTML markup that is sent to the client browser.