The PHP plug-in supports PHP and PHP extensions. Files named with the '.php' suffix are processed by the PHP interpreter. PHP can be used for dynamic page generation and general server-side processing.
The PHP plug-in configures PHP for CGI mode. That is, each time a .php file is accessed, a new PHP interpreter is run by the web server under the Common Gateway Interface (CGI) protocol. The Apache module, mod_php4.dll, is also included and the web server can be manually reconfigured to use it instead of the CGI mode.
The default plug-in configuration does not enable any PHP extensions, but a number of extensions are bundled with the plug-in, and can be loaded dynamically with the PHP 'dl()' command, or by uncommenting them in the PHP configuration file 'php.ini' in the php directory.
More information about PHP, including examples, is available from the developers of PHP.