What is the Difference Between PHP and HTML?

PHP (Hypertext Preprocessor Language) is used by web designers for programming functions that operate from a web server (usually). Some PHP functions will render information in a browser while other functions are used to store and manipulate data. Usually PHP is combined with HTML (hypertext markup language) to create websites that have functions such as logins, dynamic content (text and pictures that can easily be changed), or user interaction (shopping carts, forms, comments). The reason HTML and PHP are combined is because HTML is primarily used for the purpose of web design (visual appeal), but limited to any data functions (manipulation and storage) that it can perform. The vast majority of websites designed today (better than 95%) are built with a combination of PHP and HTML.