ASP (Active Server Pages) and PHP are server-side scripting languages, sometimes
called CGIs. Other of those scripting languages include JSP (Java Server Pages),
Perl, and plain compiled EXEs.
Basically, you can do everything with them you could do with a normal compiled
programming language. You can output imagery, text, script-code, but most
often it will be used to deliver HTML to the client.
Uses
The following are some uses of CGIs:
- Sending emails from an HTML form the user fills out
- Database-driven websites
- Webshops
- Browser-based news systems
- Keeping track of user movement along the site
- Redirecting from one page to another page without any client-side scripting like JavaScript
- Dynamically building up a navigation, for example by including a part of the HTML, or generating a dynamic menu from XML
ASP
ASPs run mostly from Windows-servers. You can also install your Personal Webserver on Windows machines, like to test your code or build your own applications. Microsoft ASPs have native support for VBScript (the default) and JScript (Microsoft's JavaScript), but you can use other languages too, like ActivePerl. Usually, PHP and JSP run on more machines, since there's working implementations on both Windows and Unix systems. ASP with VBScript makes it very easy to script code that works on both server and client-side, if some restrictions are made to the client side. You can also easily include XML, XSLT and XML DOM in ASP, using the MSXML parser.