PHP, which is an initialism for PHP: Hypertext Preprocessor, is amongst the most commonly used class-based programming languages out there. Any website or web application built using PHP will run on a given server as long as a PHP module is enabled, which renders the language absolutely universal and it’s not very unusual that there are a couple of million web servers that support it and hundreds of millions of PHP sites running on them. What makes PHP preferred over HTML is the fact that it permits you to set up a dynamic site with a myriad of different features. A PHP-based social networking website, for instance, will serve different content to each user in spite of the fact that the URL will be the same. In contrast, HTML websites are static and the content on the pages can be modified only manually. Like any other software program, PHP has different versions and the version that was used while building a specific website must be activated on the server in order for the site to work flawlessly.