ASP, or Active Server Pages, is a server-side scripting model developed by Microsoft^®, that is designed for building dynamic, interactive Web pages.

ASP evolved mainly to address the limitations of HTML, or the HyperText Markup Language. Unlike static HTML pages, ASP files can contain executable scripts that you define at design-time, and which are processed by the server at run-time.

Basically, when a Web server receives a request for an ASP file, the ASP parser interprets the scripts contained in the file and dynamically builds the response that is sent to the browser.

ASP provides a simple yet powerful means to dynamically control a Web page's output, and is generally applicable to any Web page whose output would need to be modified, or whose output would depend on input from either the user, or from an external data source.

And because ASP makes it easy to generate dynamic content for the Web, it has become the dominant platform for building powerful, interactive Web applications.

ASP .NET is the next generation of Active Server Pages technology based on Microsoft's .NET Framework. It provides an enhanced programming and runtime infrastructure that makes it even easier to develop and deploy more powerful and fully featured Web applications. And because ASP.NET is largely syntax compatibile with ASP, existing ASP applications can be augmented by gradually adding ASP.NET functionality to them.

ASP.NET applications can be written in any of the .NET-compliant programming languages, including C#, Visual Basic .NET, and JScript .NET. You can build ASP.NET files using any text editor, though ASP.NET has been designed to work seamlessly with Rapid Application Development tools as well, such as Visual Studio.

Whether you choose to build your Web pages using a RAD tool or a simple text editor, the power and benefits of innovative technologies built into the .NET Framework are readily available to any ASP.NET application. These include a managed runtime environment, type safety, inheritance, and other new and enhanced features briefly described in the following sections.