MDN Web Docs

MDN (Mozilla Developer Network) is the authoritative documentation library for Web technology, maintained by Mozilla with contributions from developers worldwide. For the standard behavior, parameters, and compatibility of every HTML/CSS/JavaScript API, it's the default reference — check MDN first for Web standards.

1. Search an API name plus “mdn” — you usually land on the exact page.
2. Check the browser compatibility table (BCD) at the bottom of the page before writing code.
3. When learning a new feature, prefer MDN's Guides over scattered blog posts.
4. The Chinese edition is community-translated and covers most core pages; the English original remains the most complete.

• Authoritative and continuously updated in step with Web standards
• Every entry ships with runnable examples
• Compatibility data comes from the BCD project maintained with browser vendors
• Free, ad-free, with Chinese and other translations