PHP is a language that has outgrown its name. It was originally conceived as a set of macros to help coders maintain personal home pages, and its name grew from its purpose. Since then, PHP's capabilities have been extended, taking it beyond a set of utilities to a full-featured programming language, capable of managing huge database-driven online environments.

As PHP's capabilities have grown, so too has its popularity. According to NetCraft (http://www.netcraft.com), PHP was running on more than 1 million hosts in November 1999. As of September 2001, that figure had already risen to over 6 million hosts, and by October 2003 PHP was reportedly installed on almost 14 million hosts. According to SecuritySpace.com, PHP is the most popular Apache module available, beating mod_ssl, Perl, and FrontPage.

PHP is officially known as PHP: Hypertext Preprocessor. It is a server-side scripting language often written in an HTML context. Unlike an ordinary HTML page, a PHP script is not sent directly to a client by the server; instead, it is parsed by the PHP engine. HTML elements in the script are left alone, but PHP code is interpreted and executed. PHP code in a script can query databases, create images, read and write files, talk to remote servers