HTML is not a programming language but a markup language. It is a foundation upon which other web programming languages depend.
HTML (Hyper Text Markup Language) is used to display web content through the internet browser of your choice (Chrome, Firefox, Internet Explorer, or your mobile device’s web browser.)
JavaScript, PHP, AJAX, and other web programming languages can be used to enhance the browsing experience, but they are all delivered through an HTML supported page. Consider HTML as the frame of the house and inserted JavaScript code (etc) to be the appliances that give it extended functionality.
While we are on the house analogy, let us not forget the paint… CSS (Cascading Style Sheet) is also a markup language and is used to stylize individual elements of an HTML page. Using CSS is a very powerful way to control everything from fonts, image variables, table-like layouts without using tables, and so much more.