PHP( Hypertext preprocessor)  is a widely-used open source general-purpose scripting language that is especially suited for web development and can be embedded into HTML. 

• Any PHP code in a requested file is executed  by the PHP runtime, usually to create dynamic web page content.
• It can also be used for command line scripting and client side GUI applications. PHP can be deployed on most web server, many operating systems  and platforms, and can be used with many relational database mangement .
• It is available free of charge, and the PHP Group provides the complete source code for users to build, customize and extend for their own use.

 
Features:

• Widely Used
• Support wide range of Databases

 
Can be used on all major Operating systems
(Linux, Unix, MS Windows, Mac OSX)
 
Support formost of the web servers.
(Apache, MS Internet, Innformaton Server, Personal Webservers)