WHATWG on 2025-02-27

04:24	<Domenic>	Psychpsyo: your archeology at https://github.com/whatwg/html/issues/10296#issuecomment-2681769263 is pretty cool. Kudos for doing that. I hope it leads to resolving this decade-old issue in a good way for all involved :)
08:02	<annevk>	Domenic: not sure I'll be ready to reply to your new `getImageData()` question later today. I've asked internally, though I would also want padenot to reply.
08:06	<Domenic>	No problem, thanks for prioritizing it.
08:56	<annevk>	And yet another polyfill appears to have poisoned the standards well. This time for scoped custom element registries. People never learn. 🫠
14:19	<Psychpsyo>	Thank you! I'm still hoping that we can restrict the cases this applies in and maybe re-phrase the spec in terms of margin collapsing once again, since that, to me, makes infinitely more sense than the current, convoluted CSS-to-English translation of Firefox's web-incompatible imitation of the behavior.
15:05	<Andreu Botella>	For the record, Chrome's implementation doesn't happen at the CSS level at all, but when actually laying out the quirky margins
15:05	<Psychpsyo>	Yes, and so does the one in IE. This is the sensible way to do it, since this is a special case of regular margin collapsing.
15:06	<Andreu Botella>	Chrome's style sheet has a special unit used only in the UA stylesheet to mark margins as quirky
15:07	<Andreu Botella>	that took me a while to figure out when I first saw it
15:07	<Psychpsyo>	That... I mean, yea... kinda not sure if there is a good way to do this.
15:07	<Andreu Botella>	https://source.chromium.org/chromium/chromium/src/+/main:third_party/blink/renderer/core/html/resources/html.css;l=47-48
15:08	<Psychpsyo>	So even the chrome way of doing this can't be written out in standard CSS. Fun.
15:42	<annevk>	I think `__qem (for quirky em)` came from WebKit. (It's still in WebKit.)
15:44	<annevk>	Oops: `// This value is used to handle quirky margins in reflow roots (body, td, and th) like WinIE. // The basic idea is that a stylesheet can use the value __qem (for quirky em) instead of em. // When the quirky value is used, if you're in quirks mode, the margin will collapse away // inside a table cell. This quirk is specified in the HTML spec but our impl is different. CSS_QUIRKY_EM`
16:44	<Psychpsyo>	I'd love to know how IE does this internally, but I assume we might never know. Overall, I am almost 100% sure that the original quirk is "any default UA margin can infinitely collapse into the top/bottom of the page and table cells." (IE does collapse into the bottom of the page, but I don't think this ever matters for web compat)
16:46	<annevk>	I don't think what IE does matters at this point. CSS_QUIRKY_EM does and fortunately is a knowable thing.
16:57	<Psychpsyo>	Yea. IE's way would mostly be a curiosity. quirky EM seems like a sensible way to do this. (Maybe not for a spec definition though)
22:36	<Meghan Denny>	feels potentially written by llm https://github.com/whatwg/html/issues/10855#issuecomment-2689176726
22:37	<Meghan Denny>	perhaps partially
23:17	<Kaiido>	feels potentially written by llm https://github.com/whatwg/html/issues/10855#issuecomment-2689176726 Nah.. this person writes in that style for years now, from before LLM was the thing it is today.