Resources for Developers,
by Developers

Documenting web technologies, including CSS, HTML, and JavaScript, since 2005.

Featured articles

New reference pages on MDN for JavaScript regular expressions

See the latest updates to the MDN reference pages about JavaScript regular expressions, including new sections on sub-features and browser compatibility information.

Using HTML landmark roles to improve accessibility

Learn what HTML landmark roles are, how they improve accessibility, and how you can include them on your website effectively.

Web APIs

Performance API

The Performance API is a group of standards used to measure the performance of web applications.

CSS

The CSS nesting module defines a syntax for nesting selectors, providing the ability to nest one style rule inside another, with the selector of the child rule relative to the selector of the parent rule.

Latest news

Responsibly empowering developers with AI on MDNblog.mozilla.org
5 months ago
Introducing AI Help: Your Trusted Companion for Web Developmentdeveloper.mozilla.org
5 months ago
Introducing the MDN Playground: Bring your code to life!developer.mozilla.org
5 months ago

Recent contributions

Contributor Spotlight

Yuji

MDN Web Docs has the most up-to-date and accurate information and the content is presented in an easy-to-understand manner. I also like that it's available in many languages (very important!).

Get involved →

Resources for Developers, by Developers