What is PHP?

PHP (Hypertext Preprocessor) is a widely-used, open-source, server-side scripting language designed specifically for web development. It was created by Rasmus Lerdorf in 1994. PHP code is executed on the server, and the result is sent to the browser as plain HTML — the client never sees the PHP code. It is embedded directly into HTML using <?php ... ?> tags. PHP can connect to databases, handle forms, create sessions, read and write files, and interact with server-side resources. It powers a huge portion of the web, including WordPress, Wikipedia, and Facebook (which used PHP at its early stages and created Hack as a typed superset).