PHP is a server-side scripting language designed for web development but also used as a general-purpose programming language. As of January 2013, PHP was installed on more than 240 million websites (39% of those sampled) and 2.1 million web servers ,originally created by Rasmus Lerdorf in 1994.
PHP code can be simply mixed with HTML code, or it can be used in combination with various templating engines and web frameworks.
The canonical PHP interpreter, powered by the Zend Engine, is free software released under the PHP License. PHP has been widely ported and can be deployed on most web servers on almost every operating system and platform, free of charge.