ASP stands for Active Server Pages, and it is Microsoft's implementation of server-side scripting. In short, this server-site scripting basically means that a script is parsed and executed by the server. When a user requests a web-page containing ASP, the web-server will parse code and send the result to the user, so the ASP code will never reach the user's browser. This is the exact opposite of JavaScript.

You don't need to be a programmer to understand ASP, but you should have some HTML knowledge, as the actual design of the web page will require it.

To use ASP scripts, you must have installed Microsoft's IIS (Internet Information Services), which is a web-server included in Windows 2000 and Windows XP Professional. It is also a part of the Windows NT 4.0 Option Pack, which can be downloaded from Microsoft's web-site. If IIS is not already installed on your computer, you can install it using the Add/Remove Programs section within the Windows Control Panel. The ASP engine is included within IIS, so you won't have to download it and install it separately. You must have Windows NT 4.0 or later to run IIS, so if you use Windows 98 you should install PWS (Personal Web Server), which is the smaller brother of IIS.

You can use ASP code to do a lot of things: dynamically edit, change or add any content to a web-page, access and query databases, read or write files, connect to remote computers, create images – the only limit is your imagination. The most obvious difference from HTML files is that ASP files have the extension ".asp", but this doesn't mean that you need to separate the ASP code from the HTML code in different files; you can use one file which will include both HTML and ASP code. The web-server won't mind at all, it will parse the ASP code and forget about the HTML code. Depending on your ASP code, the web-server will output some HTML instead of the ASP code, so the web-browser will only see HTML.

This provides a higher level of security, because nobody will be able to view your ASP code, and copy it and use it on their own web-page. Furthermore, you don't need any extra components for your web-browser, because the ASP files are returned in plain HTML, so they can be viewed in any web-browser.

In case you don't have Windows, you should know that some companies also didn't like the fact the ASP was only available for Windows platforms, so they decided to adapt ASP to other operating systems. So they created technologies like ChiliASP and iASP which allow you to take advantage of the ASP technology while using other web-servers, not just IIS. And because other web-servers run on many operating systems – like Apache web-server – this extends the ASP technology too, so it can run on other operating systems.