PHP, which is a meta-acronym for PHP: Hypertext Preprocessor, is amongst the most commonly used open-source web programming languages available out there. Any website or Internet application created in PHP will run on a given server provided that a PHP module is installed, which makes the language truly universal and it isn’t really a huge surprise that there are actually a few million servers that support it and hundreds of millions of PHP-powered sites running on them. What makes PHP preferred over HTML is the fact that it allows you to build a dynamic serving site with a lot of different options. A PHP-based social networking site, for instance, will display different web content to each user in spite of the fact that the page URL will remain the same. In comparison, HTML websites are static and the content on the pages can be edited only manually. Like any other software, PHP has several versions and the one that was used while creating a certain website must be available on the server so that the site can run flawlessly.