HTML – Hypertext Markup Language
Hypertext Markup Language (HTML) is a text-based markup language for structuring digital content, such as text, images and hyperlinks in electronic documents. HTML documents form the basis of the Internet and are displayed in web browsers. In addition to the web page content displayed in the browser, an HTML document contains additional information in the form of metadata, which includes information about the language used on the page, the author and much more. Some interesting links on the topic are provided below. Respective website language indicated in brackets.
CSS – Cascading Style Sheet
JS – JavaScript & more