Simon Pieters

It's time for Interop 2026! This is a cross-browser effort where we agree on a set of focus areas to improve compatibility.

Here's how things went in 2025, and what we're taking on for 2026: hacks.mozilla.org/2026/02/laun...

Does the XSLT implementation support `disable-output-escaping="yes"`?

Or using HTML syntax at the edges (parse and serialize) but XML tools in the middle

Is anybody still using xml/HTML polyglots for anything moder (Syntax that is valid in both html and xml)
Wondering whether those are something that needs to be considered for future HTML enhancement or a thing of the past...

Testing with software.hixie.ch/utilities/js... canShare returns false but text and url actually work on Android. So... shipping on Android at least, but there are bugs.

Jake's survey is closed.

Maybe it's not the fastness that lowers the conversion rate, but something else, like maybe the fastest websites are more likely to have not-so-great design?

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We mentioned on Winging It that we might show some of our favorite browser tips. Here's one of many that I find delightful.

If you are working with shape-outside, then Firefox has a great path editor. I made a quick video to show how it works.

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Interop 2026 is now open for proposals!

This is your chance to tell browser-makers which well-defined, well-tested features you wish had better support across browsers.

⬇️ Here's how ⬇️
github.com/web-platform...

Gecko: Intent to Ship: CSS View Transitions L1

Not saying you should but it should work

Or <script xmlns="http://www.w3.org/1999/xhtml" src="..."/>! If there's at least one element in a known namespace, browsers switch away from the XML tree view.

Right, though ARIA attributes are superglobal.

Needs bugs.webkit.org/show_bug.cgi...

Did you know?

You can style XML with CSS using
<?xml-stylesheet href="style.css"?>

Yay! It's the first Firefox release since I've joined the team, so let's take a look at some of the new developer-facing features in Firefox 142… 🧵

In your demo, the relevant element is a flex item, which is not inline.

Here's a demo showing that actual inline doesn't work: software.hixie.ch/utilities/js...

The part about display: inline is wrong.

This:

> establishes an inline formatting context and thus contains only inline-level boxes.

Refers to what the element contains. A block box establishes an inline formatting context when it has no block-level children. The element itself is still a block.

Sure. People used to call it XHTML. :) If there's an element in a known namespace browsers will apply the UA stylesheet. If you add a script element it will run (if scripting is enabled).

I don't know if feed readers will get confused though.

Want to build faster websites? Here's how:

- Learn how browsers parse, layout & paint
- Treat JS as a tool, not the foundation(!)
- Favor static HTML or server side rendering at all times
- Use Core Web Vitals alongside other metrics to learn shortfalls, improve and iterate

Then keep doing that.

It seems to me you should be able to use

<script xmlns="http://www.w3.org/1999/xhtml" src="polyfill.js"/>

Let's apply the same logic to rendering images, video and audio...

I don't know why this lad is building a subterranean city for cats, but I'm all for it.

Email is Easy Everyone knows what an email address is, right?

Email addresses are very simple, and you will score highly in this quiz.

e-mail.wtf

Yes. Remove it, Bruce! I know you can do it!

I've never used LinkedIn

No ragrets