Hypertext Pre-processor or PHP as we call it;is a server side scripting language. It is in your server and only sends the HTML to the viewer browser.It is installed in host of websites and webservers and is one of the leading languages used for websites. PHP was originally designed for web development and hence has great advantages over other languages. It can be directly embedded into an HTML source file whereas other languages (like C++) need to be called from an external file. It can also be used in Standalone graphical apps or even as a standalone shell on almost every OS out there.