keithamusRather than the same old boring internet pranks, I thought I'd build something more fun this April Fools.
CSS or BS. Can you tell your CSS properties names from BS?
Firefox for Web Developers
@firefoxwebdevs
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Official Firefox account for people who build on the web. Learn about the things we're working on to grow and improve the web platform.
Can you tell CSS from BS? I tried, and it's hard.
hasUAVisualTransition landed in Firefox 149, making it available across all major engines. As well as having a very catchy name, it lets you avoid doubling up on page transitions. Here's how it works:
If you want to experience the gross 3d transition first hand: https://simple-vt-demos.jakearchibald.com/gross-cube-transition-shaded/
hasUAVisualTransition landed in Firefox 149, making it available across all major engines. As well as having a very catchy name, it lets you avoid doubling up on page transitions. Here's how it works:
And, of course, the full documentation on MDN https://developer.mozilla.org/en-US/docs/Web/API/CloseWatcher
The CloseWatcher API landed in Firefox 149, making it easy to listen for platform-specific 'dismiss' signals. Here's how it works:
In terms of popover=hint, I dug into it when scripting a video, and… I can't make sense of the behaviour at all. Here's my investigation so far if you want to follow along: https://github.com/whatwg/html/issues/12304 & https://github.com/whatwg/html/issues/12305
Firefox 149 is out now, and adds bunch of new web platform features, such as:
🎉 The CloseWatcher API
🎉 popover=hint (although I'm concerned about the spec'd behaviour)
🎉 hasUAVisualTransition on PopStateEvent
🎉 font-family: math
🎉 The CSP reporting API
And more!
https://developer.mozilla.org/en-US/docs/Mozilla/Firefox/Releases/149
There are many browsers, but only three widely-used engines. We maintain one of those engines - Gecko. Here's why we feel that browser engine diversity is essential for the future of the web https://blog.mozilla.org/netpolicy/2026/03/23/competition-innovation-and-the-future-of-the-web/
Competition, Innovation, and the Future of the Web – Why Independent Browser Engines Matter – Open Policy & Advocacy
Gecko matters because it ensures there’s an independent voice shaping how the internet evolves. Without Gecko, the landscape would be dominated by Apple and Google alone. Is that really the ...