PHP, which is a bacronym for PHP: Hypertext Preprocessor, is one of the most famous open-source web programming languages that are available out there. Any website or Internet application built on PHP will run on a given web server as long as a PHP module is activated, which makes the language really universal and it is not really a huge surprise that there are actually a couple of million servers that support it and 100s of millions of PHP-driven websites hosted on them. PHP is preferred over HTML owing to the fact that it allows you to develop a dynamic website with a ton of different options. A PHP-based social networking site, for instance, will show unique web content to each user despite the fact that the page URL will remain unchanged. On the other hand, HTML websites are static and the content on the pages can be updated only manually. Just like any other software, PHP has different versions and the one that was used while creating a certain website must be configured on the web server in order for the site to behave flawlessly.