Firefox for Web Developers

Firefox 152 landed today, and includes web platform features like: 🎉 CSS field-sizing 🎉 Notification actions 🎉 unadjustedMovement pointer locks 🎉 getAnimations() pseudoElement option …and more! developer.mozilla.org/en-US/docs/Moz…

@rdeschain4 It's getting there bugzilla.mozilla.org/show_bug.cgi?i…

@FirefoxWebDevs How far along is customizable select?

Firefox 152 landed today, and includes web platform features like: 🎉 CSS field-sizing 🎉 Notification actions 🎉 unadjustedMovement pointer locks 🎉 getAnimations() pseudoElement option …and more! developer.mozilla.org/en-US/docs/Moz…

Someone said our Instagram page looks like "the world's most boring game of Guess Who" 😭 instagram.com/firefoxwebdevs…

Ohhhh this has just been added to WebKit bugs.webkit.org/show_bug.cgi?i…

@gzamann If you give me more details about any/all of those I can look into it. Ideally, a reproducible demo of the issue.

@samwhoo Absolutely. His cell is intact.

@FirefoxWebDevs The fake background isn’t fooling me, I know you still have Jake locked up in there.

Notification actions landed in Firefox 152, allowing you to add quick action buttons to your notifications. Here's how they work:

@dalu_hey Yep, 'no' is perfectly valid as a notification action id and/or title.

@FirefoxWebDevs how about no

And here's the full showNotification docs on MDN developer.mozilla.org/en-US/docs/Web…

@eyebrows360 Sorry I didn't have much more insight other than "turn it off and on again" hah

@FirefoxWebDevs Got to the point where I had to restart it, and now it's seemingly fine again. Thank you for the help on this!

@FirefoxWebDevs After latest update I'm getting way more crashed tabs, and now youtube.com URLs will sometimes just refuse to load entirely - have had to start copying the URL from the address bar and opening 3+ more tabs with it in, to try get it to load.

@eyebrows360 Oh, wow. Um. Is it still hanging, or are you getting a particular error?

@FirefoxWebDevs Now they're failing to load every single time. Guess restarting FF might help but I've got too many things I can't close right now so will have to try that later

@eyebrows360 hmmm so it's smelling like some broken cookie state. Could you try clearing site data for youtube?

@FirefoxWebDevs Intriguingly I tried in a private window and it loaded ok every single time. It's only non-private ones where it's happening. All my extensions are active in private mode too.

@eyebrows360 Are there any tabs that reliably reproduce the crash, or is it ~random? Are you confident it isn't related to extensions?

@FirefoxWebDevs Sorry, yes, regular release, 152.0.2 on Windows 11 (locked to 23H2). ~8 windows open permanently, many dozens of tabs. Only tend to restart FF when it crashes, which is usually every few weeks. Since last crash (& thus update on reloading) a few days back this YT issue started.

@xkit Yes, it starts of default-safe. You have to be mindful about further things you enable, and think through the consequences.

@FirefoxWebDevs setHTML is not an innerHTML drop-in replacement. It's a METHOD. Its default config strips developer-authored markup (data-*, etc.). Using it to filter out unsafe XSS <script>, javascript:, on*, etc forces config ceremony. That adds complexity.

The Sanitizer API landed in Firefox 148, along with element.setHTML(). This lets you fully configure how HTML strings are cleaned as they're parsed. hacks.mozilla.org/2026/02/goodby…

@xkit Correct, you have to be mindful about what you want to allow. This is a good thing.

@FirefoxWebDevs setHTML requires the santizer config clunk just to make it work. href is allowed but checked for `javascript:`, but data-* and tabindex are stripped without inspection unless sanitizer-whitelisted. That's heavy ceremony, not a drop-in replacement for innerHTML.

The full docs on MDN developer.mozilla.org/en-US/docs/Web…

CSS field-sizing is newly baseline, meaning you can make various form fields size to their contents, without needing JavaScript.

@Maduemezia90188 We had some compatibility issues with sites, so we had to ship the subset. It's kinda sad that it happens, but it does.

@FirefoxWebDevs Question to Firefox: Why did you support the limited subset for the ::-webkit-scrollbar and the other elements? I am aware that it's to limit the overlay content of the web in general, but I still feel that it's completely unnecessary.

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