@developer.mozilla.org
The official MDN Web Docs account, now on Bluesky. We deliver the best web docs around.
Visit → https://mdn.dev
Contribute → https://mdn.dev/community
@webdevs.firefox.comReposted by @developer.mozilla.orgWhat do you want us to work on in 2027?
Here's a web app where you can rank the Interop proposals you care about, giving us data we can use to prioritise feature development.
@webdevs.firefox.comReposted by @developer.mozilla.orgFirefox 157 has landed, and includes a couple of useful CSS features: 🎉 at-rule() in @supports - lets you limit rules to browsers that support a given at-rule. 🎉 overscroll-behavior: chain - lets scrolling pass up to parent elements, but prevents UA effects like 'bounce' and overscroll. …And more!
@developer.mozilla.org🆕 Customize MDN's browser compat tables!
Press ⚙️ Settings on any compat table to choose which browsers and engines you see, and hide the ones you don't need.
Your picks are saved in your browser.
@webdevs.firefox.comReposted by @developer.mozilla.orgWhen and how CSS custom property values are calculated might not be what you expect, and it has a big impact on your styles…
@webdevs.firefox.comReposted by @developer.mozilla.orgMajor versions of Firefox now land every two weeks, so Firefox 155 dropped today with web platform features including:
🎉 Fully typed CSS attr()
🎉 CSS progress()
🎉 Promise.allKeyed() and allSettledKeyed()
🎉 Lots of new WebTransport stuff
…And more!
@webdevs.firefox.comReposted by @developer.mozilla.orgCSS attr() now works on all properties in Firefox 155. Here's how it works, and how to get the most out of it:
@developer.mozilla.org🆕 Introducing the MDN MCP server!
Bring MDN's docs and browser compat data straight into your AI agent or IDE for accurate, up-to-date answers about the web platform.
No more outdated guesses from training data.
Learn more 👇
developer.mozilla.org/en-US/blog/introducing-mdn-mcp-server/
@developer.mozilla.orgCreate frosted glass effects in CSS 🪟
backdrop-filter applies visual effects to the content behind an element - blur, brightness, contrast, and more.
backdrop-filter: blur(10px) brightness(0.9);
No JavaScript. No canvas tricks.
Learn more 👇
developer.mozilla.org/en-US/docs/...
@developer.mozilla.orgSupport dark mode with one CSS property 🌙
color-scheme tells the browser your page supports light, dark, or both. Form controls, scrollbars, and system colors adapt automatically.
> :root { color-scheme: light dark; }
Learn more 👇
developer.mozilla.org/en-US/docs/...
@developer.mozilla.orgHold object references without preventing garbage collection 🗑️
`WeakRef` lets you reference an object while allowing it to be GC’d if nothing else holds a strong reference. Use for caches, and pair with FinalizationRegistry.
Learn more 👇
developer.mozilla.org/en-US/docs/...
@developer.mozilla.orgRead and write to the clipboard with the modern Clipboard API 📋
async/await, permission-aware, and way cleaner than execCommand.
⋅ Supports text, HTML, and images
⋅ Works in secure contexts (HTTPS)
⋅ No Flash. No hacks.
Learn more 👇
developer.mozilla.org/en-US/docs/...
