Anne van Kesteren
annevk.nl
Anne van Kesteren
@annevk.nl
Web Standards Engineer at U+F8FF.
Evergreen sentiment. (If you always wanted to be a specification editor, wiki.whatwg.org/wiki/Specs/t... has some suggestions. Most still relevant.)
We *really* need a specification for hit testing on the web...
October 7, 2025 at 6:49 AM
Reposted by Anne van Kesteren
Web component folks: A common feature with request is to "inherit from a button". If that's something you want, which specific button behaviours is it you want to inherit? Why is putting a button in the shadow root not the answer?
September 29, 2025 at 12:12 PM
Reposted by Anne van Kesteren
I got permission to share this, and I'm extremely grateful for that.

The Onion got this letter from one of our subscribers in Alaska. She works with dementia patients and decided to leave a copy in the car for each one.

This email made my year. Read it and you'll see what I mean. People are good.
July 1, 2025 at 6:46 PM
APNG finally graduated from its MozillaWiki documentation to a proper standard: www.programmax.net/articles/png...
PNG is back!Rec. 2020 and Rec. 709 comparison
After 20 years, PNG is back with renewed vigor! A new PNG spec was just released.
www.programmax.net
June 24, 2025 at 1:15 PM
If you want to learn more about Declarative Web Push or Web Push in general, my colleague Brady put out a great video: developer.apple.com/videos/play/...
Learn more about Declarative Web Push - WWDC25 - Videos - Apple Developer
Learn how Declarative Web Push can help you deliver notifications more reliably. Find out how to build on existing standards to be more...
developer.apple.com
June 11, 2025 at 6:08 AM
Reposted by Anne van Kesteren
If you write code to make websites (HTML, CSS, JS, Web API, Media) and you get frustrated trying to wrangle your code to work in Safari, which bugs are blocking you? Which existing features would you most like to see improved? If you got a chance to order priorities which effort would you put first?
May 2, 2025 at 4:51 PM
Reposted by Anne van Kesteren
Please don't publish / release a polyfill for unshipped Web features. Someone is bound to use it in production and ruin it for everyone else.
February 28, 2025 at 6:48 AM
And yet another polyfill appears to have poisoned the standards well. This time for scoped custom element registries. People never learn. 🫠
February 27, 2025 at 10:15 AM
I have at times told people that if you want to generate XML, you should use a serializer. So when I had to generate a serialized CSS URL value containing a data: URL of an SVG document of which colors could vary, I immediately went for string manipulation and concatenation. 😅
January 23, 2025 at 7:36 AM
Reposted by Anne van Kesteren
📅 Save the dates! The Web Engines Hackfest 2025 will take place June 2-4 in A Coruña, Galicia (Spain).
Check more details at: webengineshackfest.org
2025 Web Engines Hackfest
Web Platform community event for people working on the different engines (Chromium/Blink/V8, Safari/WebKit/JSC, Firefox/Gecko/SpiderMonkey, Servo, Ladybird), on the testing side (WPT, Test262), or on ...
webengineshackfest.org
January 20, 2025 at 9:24 AM
The aliens are coming and their goal is to invade and destroy Earth.
In the jungle I must wait until the dice roll five or eight
January 6, 2025 at 3:12 PM
Almost time to sign off for the year. Web standard proposals to finish in (early?) 2025:

- Declarative Web Push
- Scoped Custom Element Registries
- HTML (and SVG & MathML) Sanitizer API
- moveBefore()
- fetchLater()
- float16 in 2D canvas
- <button command>

and quite a few more. Happy holidays!
December 19, 2024 at 3:49 PM
git blame as visualized by GitHub (or Searchfox for the HTML standard) is an amazing development tool for projects that span decades. In particular for projects that enforce good commit messages. Being able to answer why something is the way it is, can be crucial when changing it.
December 18, 2024 at 7:42 AM
Reposted by Anne van Kesteren
@annevk.nl and I worked on a refined proposal to untie scoped element registry from shadow DOM so that you can use a scoped registry without shadow DOM. Your feedback is appreciated:
github.com/whatwg/html/...
Revamped Scoped Custom Element Registries · Issue #10854 · whatwg/html
https://github.com/WICG/webcomponents/blob/gh-pages/proposals/Scoped-Custom-Element-Registries.md is a good proposal, but it ties the functionality too much to shadow roots. This is Ryosuke and I's...
github.com
December 14, 2024 at 12:37 AM
Reposted by Anne van Kesteren
We implemented a new value for `background-clip` called `border-area`. It lets you use CSS fill a border with a background image or gradient.

This article explains how it works, and shows up the possibilities in 7 demos.

#css #webdesign #webdevelopment #graphicdesign

webkit.org/blog/16214/b...
Make creative borders with background-clip border-area
How’d you like to use CSS to easily create a border from an image or gradient?
webkit.org
November 20, 2024 at 4:03 PM
The increased URL interoperability between browsers motivated me to do another pass at the remaining open issues. Fully solving file: URLs and URL parsing overall feels within reach for 2025. The IDNA BiDi issue depends on Unicode, but it is scheduled for Unicode 17.0.
December 3, 2024 at 3:38 PM
This seems like a great idea at first, except that it is very ASCII-compatible-alphabets-centric and ASCII has confusables as well, e.g., l vs I. Passkeys are the answer.
Great question! Punycode is a representation of Unicode with the limited ASCII character subset used for Internet hostnames.
I turn this off in our browsers at work to avoid homoglyph attacks.
en.m.wikipedia.org/wiki/Punycode
November 30, 2024 at 7:41 AM
After working on URLs for well over a decade, we finally hit a point where real browser convergence on core aspects is happening. Experimental browser builds are at ~96% (Chromium), ~99% (Gecko), and ~100% (WebKit) in Interop 2024’s URL category. Very exciting to see! Kudos!
November 29, 2024 at 6:19 PM
Reposted by Anne van Kesteren
www.keithcirkel.co.uk/100-patches-...
100 patches to 5 browsers in 18 months.
100 patches to 5 browsers in 18 months
I went on a journey to contribute more to browsers, here's that story.
www.keithcirkel.co.uk
November 25, 2024 at 6:45 PM
Reposted by Anne van Kesteren
Just look at that Interop 2024 score…
wpt.fyi/interop-2024
November 22, 2024 at 6:28 PM
It seems chain letters are still alive somehow.
November 22, 2024 at 10:08 AM
If your website does its own video controls, please adopt the :volume-locked pseudo-class to determine whether to offer volume control. Notably iOS and iPadOS manage their volume globally.
November 22, 2024 at 10:02 AM
Reposted by Anne van Kesteren
My colleague @serena.nz gave an amazing PurpleCon talk describing the behind-the-scenes experience of removing the (in?)famous lock icon from Chrome: www.youtube.com/watch?v=iUAx...

One day I aspire to get as many laughs during a talk as a 90s sitcom laugh track 🤩
"🙋❓🙋 why❓🤔 chrome 🌐 🙅🚫 removed 🚫🙅 the 🔒 lock 😮 icon 🤷🤷" - serena chen (purplecon 2024)
YouTube video by purplecon
www.youtube.com
November 15, 2024 at 12:32 AM
In London for the HTTP Workshop. 🎡
November 12, 2024 at 11:03 AM