PHP, also known as PHP: Hypertext Preprocessor, is an open-source scripting language and interpreter. It is used primarily on UNIX Web servers to create interactive and customized Web pages and is an alternative to Microsoft Active Server Page (ASP) technology.
When PHP script is embedded within a Web page, the Web server calls PHP to interpret and perform the operations specified in the PHP script. Web pages with embedded PHP script can use the file extensions .php, .php3 or .phtml (if you have added this mime-type). For simplicity, we recommend the use of ".php" to refer to all PHP-based web pages.