PHP, which is a recursive initialism for PHP: Hypertext Preprocessor, is among the most commonly used general-purpose server-side coding languages that are available out there. Any website or web application created with PHP will run on a given web server as long as a PHP module is enabled, which makes the language absolutely universal and it is hardly unusual that there are several million servers that support it and 100s of millions of PHP sites running on them. PHP is preferred over HTML thanks to the fact that it permits you to develop a dynamic serving website with loads of options. A PHP-based social network, for instance, will serve different web content to each user regardless of the fact that the page URL will remain the same. In contrast, HTML sites are static and the page content can be edited only manually. Just like any other software program, PHP has different versions and the one that was used whilst building a specific website must be enabled on the server so that the site can run properly.