PHP

PHP is used by over 80% of all websites, and for a good reason. It's a fast and beginner-friendly way to let your server do awesome things for your website. Getting a server environment running with PHP is easy, and from that moment on, the possibilities are endless. You can create a blog, or an MMORPG, or an ecommerce website, or a user account system – the sky's the limit! Or, well, your server's capacity is the limit.

Prerequisites: Intermediate HTML and CSS knowledge, some JavaScript helps too