What is PHP

PHP (recursive acronym for 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.

The basic syntax :
<?php
 echo "Hello World";
?>

What PHP do:

PHP is a server side scripting language. By the php scripting language we can able to develop static content and dynamic content html webpages. PHP can communicate with mysql database directly.  

PHP Features:

• Fully server side scripting language : Output will be in the html mark up tags and accessed by the WEB browser.
• Command Line Scripting
• Platform Independent
• Cross browser support
• Zend Engine optimization
• Direct support to MySql database connectivity.
• PHP outputs pdf files, images, and multimedia attachments directly to the web browser. 
• It supports most of webservers like apache, tomcat, nginx, glassfish, and IIS etc.