Sandbox::https://github.com/mdn/content/pull/45958

Josh-Cena · 2026-10-03T00:57:12Z

We have well-defined policies on whitelisted polyfill sources (core-js and es-shims), but we also have many ad-hoc polyfill links. While we can probably keep the ones that are still useful, the other ones only add noise and maintenance burden.

In an effort to reduce excessive external links, I'm removing these outdated polyfills whose features are already baseline.

github-actions · 2026-10-03T00:58:54Z

Preview URLs (14 pages)

External URLs (90)

URL: /en-US/docs/Web/API/Crypto/subtle
Title: Crypto: subtle property

https://vibornoff.github.io/webcrypto-examples/index.html (1 time)

URL: /en-US/docs/Web/API/MediaStream_Recording_API
Title: MediaStream Recording API

https://blog.addpipe.com/mediarecorder-api/ (1 time)
https://blog.addpipe.com/safari-technology-preview-73-adds-limited-mediastream-recorder-api-support/ (1 time)
https://github.com/chrisjohndigital/OpenLang (2 times)
https://github.com/chrisjohndigital/TutorRoom (2 times)
https://github.com/samdutton (1 time)
https://quickblox.github.io/javascript-media-recorder/sample/ (1 time)
https://simpl.info/mediarecorder/ (1 time)

URL: /en-US/docs/Web/API/Pointer_events/Pinch_zoom_gestures
Title: Pinch zoom gestures

URL: /en-US/docs/Web/API/ReadableStreamDefaultController
Title: ReadableStreamDefaultController

https://mdn.github.io/dom-examples/streams/simple-random-stream/ (1 time)

URL: /en-US/docs/Web/API/Server-sent_events
Title: Server-sent events

https://docs.adonisjs.com/guides/digging-deeper/server-sent-events (1 time)
https://github.com/EventSource/eventsource (1 time)
https://github.com/mozilla/webowonder-demos/tree/master/demos/friends%20timeline (1 time)
https://hacks.mozilla.org/2011/06/a-wall-powered-by-eventsource-and-server-sent-events/ (1 time)
https://intercoolerjs.org/docs.html (1 time)
https://mercure.rocks/ (1 time)

URL: /en-US/docs/Web/API/Web_Animations_API/Web_Animations_API_Concepts
Title: Web Animations API Concepts

https://codepen.io/collection/nqNJvD (1 time)
https://drafts.csswg.org/css-animations/ (1 time)
https://drafts.csswg.org/css-transitions/ (1 time)
https://hacks.mozilla.org/2016/08/animating-like-you-just-dont-care-with-element-animate/ (1 time)

URL: /en-US/docs/Web/API/Window/structuredClone
Title: Window: structuredClone() method

https://github.com/zloirock/core-js (2 times)

URL: /en-US/docs/Web/API/WorkerGlobalScope/structuredClone
Title: WorkerGlobalScope: structuredClone() method

https://github.com/zloirock/core-js (2 times)

URL: /en-US/docs/Web/JavaScript/Reference/Statements/function*
Title: function*

https://en.wikipedia.org/wiki/Inversion_of_control (1 time)
https://github.com/getify/You-Dont-Know-JS/blob/1st-ed/async%20%26%20performance/ch4.md (1 time)
https://github.com/mozilla/task.js (1 time)
https://medium.com/@raihan_tazdid/callback-hell-in-javascript-all-you-need-to-know-296f7f5d3c1 (1 time)
https://youtu.be/qbKWsbJ76-s (1 time)

URL: /en-US/docs/Web/MathML/Guides/Authoring
Title: Authoring MathML

https://asciimath.org/ (1 time)
https://en.wikipedia.org/wiki/Handwriting_recognition (1 time)
https://en.wikipedia.org/wiki/LaTeX (1 time)
https://en.wikipedia.org/wiki/Lightweight_markup_language (2 times)
https://en.wikipedia.org/wiki/Optical_character_recognition (1 time)
https://en.wikipedia.org/wiki/WYSIWYG (1 time)
https://fred-wang.github.io/MathFonts/ (1 time)
https://fred-wang.github.io/MathFonts/XITS/mathfonts.css (1 time)
https://fred-wang.github.io/TeXZilla/examples/customElement.html (1 time)
https://github.com/brucemiller/LaTeXML/wiki/Integrating-LaTeXML-into-TeX-editors (1 time)
https://github.com/fred-wang/TeXZilla (1 time)
https://github.com/fred-wang/TeXZilla/wiki/Using-TeXZilla (1 time)
https://github.com/wikimedia/mediawiki-services-mathoid (1 time)
https://math.nist.gov/~BMiller/LaTeXML/ (1 time)
https://mathscribe.com/author/jqmath.html (1 time)
https://nodejs.org/ (1 time)
https://webdemo.myscript.com/views/math/index.html (1 time)
https://www.libreoffice.org/ (1 time)
https://www.lyx.org/ (1 time)
https://www.mediawiki.org/wiki/MediaWiki (1 time)
https://www.seamonkey-project.org/ (1 time)
https://www.texmacs.org/tmweb/home/welcome.en.html (1 time)
https://www.thunderbird.net/en-US/ (1 time)
https://www.w3.org/wiki/Math_Tools (1 time)

URL: /en-US/docs/Web/Media/Guides/Audio_and_video_delivery
Title: Audio and video delivery

https://archive.org/ (1 time)
https://caniuse.com/ (1 time)
https://caniuse.com/mp3 (1 time)
https://caniuse.com/mpeg4 (1 time)
https://caniuse.com/ogg-vorbis (1 time)
https://caniuse.com/ogv (1 time)
https://caniuse.com/webm (1 time)
https://dvcs.w3.org/hg/html-media/raw-file/tip/media-source/isobmff-byte-stream-format.html (1 time)
https://en.wikipedia.org/wiki/Digital_rights_management (1 time)
https://en.wikipedia.org/wiki/M2ts (1 time)
https://flowplayer.com/ (1 time)
https://github.com/kripken/speak.js/ (1 time)
https://hacks.mozilla.org/2014/06/easy-audio-capture-with-the-mediarecorder-api/ (1 time)
https://handbrake.fr/ (1 time)
https://howlerjs.com/ (1 time)
https://jPlayer.org/ (1 time)
https://m.vid.ly/ (1 time)
https://mdn.github.io/webaudio-examples/decode-audio-data/promise/ (1 time)
https://serversideup.net/open-source/amplitudejs/ (1 time)
https://sourceforge.net/projects/audacity/ (1 time)
https://videojs.org/ (1 time)
https://w3c.github.io/encrypted-media/ (1 time)
https://w3c.github.io/media-source/ (1 time)
https://www.ffmpeg.org/ (1 time)
https://www.firefogg.org/ (1 time)
https://www.getmiro.com/ (1 time)
https://www.mediaelementjs.com/ (1 time)
https://www.schillmania.com/projects/soundmanager2/ (1 time)
https://www.sublimevideo.net/ (1 time)

URL: /en-US/docs/Web/Performance/Guides/Fundamentals
Title: Performance fundamentals

Josh-Cena · 2026-10-03T00:57:51Z


-#### Make events immediate
-
-As old-school, accessibility-aware Web developers we love click events since they also support keyboard input. On mobile devices, these are too slow. You should use {{domxref("Element/touchstart_event", "touchstart")}} and {{domxref("Element/touchend_event", "touchend")}} instead. The reason is that these don't have a delay that makes the interaction with the app appear sluggish. If you test for touch support first, you don't sacrifice accessibility, either. For example, the Financial Times uses a library called [fastclick](https://github.com/ftlabs/fastclick) for that purpose, which is available for you to use.


This hasn't been the case since forever ago

Josh-Cena · 2026-10-03T00:59:03Z

-#### Fallback for browsers without MathML support
-
-It is recommended to provide a fallback mechanism for browsers without MathML support. If your document contains only basic mathematical formulas then a small [mathml.css](https://github.com/fred-wang/mathml.css) stylesheet might be enough. To load it conditionally, just insert one line in your document header:


I'm not sure if there are still merits in using custom CSS for MathML (probably yes; default MathML looks a bit ugly to me) or even using MathJax/KaTeX (if you value client-side generation, I guess). But they certainly shouldn't be presented as a polyfill mechanism.

chrisdavidmills

I'm familiar with many of these features, and I have checked the support status for the ones I'm less familiar with. I think all of these changes made sense.

This is a wide-ranging PR, so I'll approve it, but I think we should leave it open for a couple of days in case anyone else wants to jump in and comment.

Josh-Cena · 2026-10-05T20:43:21Z

OK thanks! As usual I'll hold it until my Friday.

Remove GH polyfill links to baseline features

202578e

Josh-Cena requested review from a team as code owners October 3, 2026 00:57

Josh-Cena requested review from chrisdavidmills, fred-wang and sideshowbarker and removed request for a team October 3, 2026 00:57

github-actions Bot added Content:WebAPI Web API docs Content:JS JavaScript docs Content:Media Media docs Content:MathML MathML docs Content:Performance Web performance docs size/m [PR only] 51-500 LoC changed labels Oct 3, 2026

Josh-Cena commented Oct 3, 2026

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chrisdavidmills approved these changes Oct 5, 2026

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Josh-Cena merged commit 47b1321 into mdn:main Oct 10, 2026
8 checks passed

Josh-Cena deleted the rm-polyfill branch October 10, 2026 01:08

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Remove GH polyfill links to baseline features - #45958

Remove GH polyfill links to baseline features#45958
Josh-Cena merged 1 commit into
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Josh-Cena:rm-polyfill

Josh-Cena commented Oct 3, 2026 •

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		#### Make events immediate

		As old-school, accessibility-aware Web developers we love click events since they also support keyboard input. On mobile devices, these are too slow. You should use {{domxref("Element/touchstart_event", "touchstart")}} and {{domxref("Element/touchend_event", "touchend")}} instead. The reason is that these don't have a delay that makes the interaction with the app appear sluggish. If you test for touch support first, you don't sacrifice accessibility, either. For example, the Financial Times uses a library called [fastclick](https://github.com/ftlabs/fastclick) for that purpose, which is available for you to use.

		#### Fallback for browsers without MathML support

		It is recommended to provide a fallback mechanism for browsers without MathML support. If your document contains only basic mathematical formulas then a small [mathml.css](https://github.com/fred-wang/mathml.css) stylesheet might be enough. To load it conditionally, just insert one line in your document header:

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Josh-Cena commented Oct 3, 2026 •

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