What Is HTML?
HTML (HyperText Markup Language) is the language that describes the structure and meaning of a web page. Every page you have ever opened in a browser is, underneath, an HTML document.
<h1>Moon Facts</h1>
<p>The Moon is about <strong>384,400 km</strong> from Earth.</p>
<ul>
<li>It has no atmosphere to speak of.</li>
<li>The same side always faces us.</li>
</ul>
<a href="https://science.nasa.gov/moon/">Read more at NASA</a>
A browser shows this as a large heading, a paragraph with the distance in bold, a bulleted list with two items, and a clickable link.
HTML is a markup language, not a programming language:
- You mark up content with tags such as
<h1>and<p>that say what each piece of content is — a heading, a paragraph, a list, a link. - There are no variables, loops, or calculations. For behavior you add JavaScript; for appearance you add CSS.
- Browsers are forgiving: a page with mistakes still displays, which is friendly for beginners but means mistakes can hide. You'll learn to catch them with a validator.
The three languages of the web
| Language | Job | Example |
|---|---|---|
| HTML | Structure and meaning | "This is a heading, this is a button" |
| CSS | Presentation | "Headings are dark blue and 2rem tall" |
| JavaScript | Behavior | "When the button is clicked, open the menu" |
A living standard
HTML was created by Tim Berners-Lee in 1991. Today it is maintained by the WHATWG (a group formed by the browser makers) as the HTML Living Standard — one continuously updated specification instead of numbered versions. "HTML5" was the last numbered name; you'll still see it used to mean "modern HTML". This course teaches the current standard and notes when a feature is new enough that you should check browser support.