What is ASP (Active Server Pages) and why is it still used?

Active Server Pages, or ASP for short, is Microsoft's solution to producing dynamic content for web sites. It is old and dates back to the 1990s and NT Server or the desktop operating systems of Windows 95 and 98.

It is a script based system that allows simple programme code to be added to the text of an HTML file and this code is executed on the server. The end result of running this code is an HTML page sent to the browser. The file extension of an ASP script is .asp, although server settings allow this to be changed. Several languages can be used in the scripts with VBScript being the most common. Jscript is sometimes used, as is Perlscript.

Why is ASP so powerful?

The real power of ASP is in its simplicity. If is very easy to add a few lines of programme code to read the results of an online form or the parameters included in a URL. It is not too difficult to return database results. These tools are enough to make a website into an interactive application instead of just text and pictures. Powerful results can be achieved without the need for advanced programming skills.

What are the limitations?

ASP is not a compiled language so it is slow if it is performing any serious processing. It has limited data structures and cannot call the Windows API functions.

Can the functionality be extended?

ASP supports ActiveX and COM, so it can use a wide range of components supplied with Windows as well as third party components, such as the components we produce. Built in Windows components can provide support for file handling, database connectivity, XML and HTTP. We have components for image editing, saving file uploads and dynamically creating zip archives. So if more functionality is required in an ASP application, it can be included.

Why is ASP still used after all this time?

There is a certain amount of inertia when it comes to implementing new technology. If an application works, there is no need to replace it. If an application needs some modifications, it is often easier to make those modifications and keep the underlying technology unchanged rather than rewrite the whole application. People prefer to use their existing skills and knowledge where possible, rather than learning new skills. There are a lot of existing ASP applications and a lot of developers who are happy to continue using ASP. In addition, the "replacement" to classic ASP, ASP.NET is not a direct replacement. It is a very powerful programming environment with a comprehensive set of classes, allowing a web developer to achieve far more than ASP alone could, but it is difficult to use. Many web developers have been reluctant to take that route and prefer to work with the older and simpler system. ASP is surprisingly widely used over 20 years after it was first introduced.