PHP stands for PHP Hypertext Preprocessor. It is a server-side programming language specifically designed for creating dynamic web pages. The language was originally developed in 1994 by Rasmus Lerdorf and has since been expanded to become one of the WWW's most popular scripting languages. According to 2005 Netcraft statistics, PHP is currently being used in over 23,000,000 domains. Like other types of server-side languages such as ASP, ASP.NET, and JSP, PHP code is processed on the web server and generates the XHTML code or other output that can be viewed in the browser. Unlike other server-side languages, PHP is an open source product, meaning everyone has access to the source code and can use, alter, and redistribute it all without charge.
The current version of PHP and the version covered in this tutorial is 5. This tutorial is by no means a complete coverage of the PHP language. It is designed to demonstrate some of the most common features and applications of PHP.
PHP 5 can be run on just about any type of operating system and Web server. However, in order for PHP scripts to be processed, the PHP interpreter must be installed. The software is available in two forms - complete source code and executable binaries. These days, most Linux systems come with the PHP source code. For non-Unix/Linux systems, binaries can be downloaded at http://www.php.net/downloads.php.
For more information about PHP, please visit http://www.php.net.