PHP, which is a meta-acronym for PHP: Hypertext Preprocessor, is one of the most commonly used programming languages that are available out there. Any website or web app built on PHP will run on a given web server provided that a PHP module is enabled, which makes the language really universal and it is not really a big surprise that there are actually a few million servers that support it and hundreds of millions of PHP websites hosted on them. PHP is preferred over HTML because it allows you to create a dynamic serving website with heaps of features. A PHP-based community website, for example, will show different web content to each user although the page URL will not change. By 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 version that was used whilst developing a specific website must be enabled on the web server in order for the site to run flawlessly.