The most common way to provide dynamic content on Web sites is with CGI (Common Gateway Interface) programs. The CGI is a specification of communication between server processes (such as programs that generate dynamic documents) and the server itself. Server-Side Includes (SSIs) allow output from CGI programs, or other programs, to be inserted into existing HTML pages.
Another way to add dynamic content to your Web site is to use PHP. This is an HTML-embedded scripting language that was designed specifically for Web usage. The PHP module for Apache is one of the most popular third-party modules available.
By default, you may put any CGI program in the ScriptAlias directory on your server. These programs must be executable ...