Being able to write:

  <script src="util.js" />

instead of:

  <script src="util.js"></script>

would be nice. But it's not (iirc) compatible with WHATWG's HTML5 parsing algorithm, browsers only use XML mode if served the correct content type, and in XML mode they don't recover at all from errors (when really, they should show an annoying popup and then switch to a quirks parser).

We need to fix that, before XHTML can be viable. As-is, it's like it's being sabotaged.

Maybe web shops must stop producing malformed documents. No one else expects a corrupt pdf, xlsx, exe, jpg, etc to work. Ability to show incorrect documents. What an absurd requirement. If it’s incorrect, fuken correct it man, or get a simpler job.

Microsoft Excel has quite a bit of code dedicated to opening corrupt XLSX files. Pretty sure Adobe Reader does stuff with corrupt PDFs, too. The ability to show incorrect documents is important if you care more about reading the document than technical correctness.

> they don't recover at all from errors

This is a recurring argument I see against XHTML. Fundamentally I don’t see it as a downside (you don’t expect the browser to run malformed JavaScript – why not HTML, too?). I agree there’s a couple of possible obstacles, though:

1. It can be hard to produce 100% valid XHTML by hand – I personally run into errors from time to time. This is actually something an LSP could help with! All these errors can be detected at authoring time, given the proper tooling.

2. Naive template systems might produce invalid XHTML if you’re not careful. Personally I haven’t run into such situations, but some people say they do.

This is also a tooling problem, but it’s a bit trickier to tackle. A solution could be either (1) an LSP for the templating system, working together with the (X)HTML LSP, or (2) a templating system that is XML-native (but more ergonomic than XSLT haha).

(Personally, I’m thinking about starting something like (2) with Jinja-like syntax, but I feel it’s not something I have the time or energy for, at this point.)

> when really, they should show an annoying popup and then switch to a quirks parser

Not sure if it’s a good solution long-term, but I see how that could help with adoption, so I’m all for it.

> you don’t expect the browser to run malformed JavaScript

Refer to https://tc39.es/ecma262/2024/multipage/ecmascript-language-l... (extract below)

---

In contrast, the source

  { 1
  2 } 3

is also not a valid ECMAScript sentence, but is transformed by automatic semicolon insertion into the following:

  { 1
  ;2 ;} 3;

which is a valid ECMAScript sentence.

That's a weird wording, huh. I would interpret it not as yeah this is invalid code but we fix it for you, but rather this code would be invalid if not for this weird exception we carve out for it.

I would love to say “let's abolish ASI too”, but (1) some folks genuinely use it assuming that it's a syntax feature and not a compat thing, and (2) it's a compat thing, meaning it's not getting removed without a very valid reason. A shame, though.

But JS parsing is still undeniably way more strict than HTML, no?

How about Appendix B? https://tc39.es/ecma262/2024/multipage/additional-ecmascript...

> These features are not considered part of the core ECMAScript language. Programmers should not use or assume the existence of these features and behaviours when writing new ECMAScript code. ECMAScript implementations are discouraged from implementing these features unless the implementation is part of a web browser or is required to run the same legacy ECMAScript code that web browsers encounter.

Some of these are legacy APIs, but some of them are just plain syntax errors.

Interviewer: "So what's your professional opinion about this annoying popup that blocks the main thread?"

Interviewee: "I see how that could help with adoption, at least until we are able to migrate to a red single-line error with a long-ass-scrollbar that displays instead of rendering any of the page at all."

Interviewer: "Thanks. We'll be in touch."

I'm assuming it's just a joke for the sake of joke, but please re-read my and GP's comments again. This is not a solution we're discussing.

> Be kind. Don't be snarky. Converse curiously; don't cross-examine. Edit out swipes.

> Please respond to the strongest plausible interpretation of what someone says, not a weaker one that's easier to criticize.

– https://news.ycombinator.com/newsguidelines.html

> Can we also go to XHTML5, while on it?

Personally, I would like that, but in practice I don't think it's ever going to be a thing, so I didn't even bother adding support for it in SuperHTML, sorry!

Totally understandable, you do you! But I think the problem is, it’s not yet a thing because of the lack of tooling. It is kind of a chicken and egg situation here.

Would you perhaps be open to a PR, maybe? (I would love to work on something like that, although I’m swamped right now and can’t promise anything.)

Yes, I'd be open to a PR, but I think the other comment on lack of browser support is the actual obstacle and really don't see that changing easily.

What's missing in browsers for XHTML5? Don't they understand and validate the XML and allow using the HTML5 elements when some page is served with a application/xhtml+xml mimetype? Don't they, at worst, degrade to html5 parsing?

(I only tried writing polyglot syntax, with only stuff allowed in both XHTML and HTML syntaxes)

Or are you concerned with the unrecoverable mechanism?

I used to write XHTML and it took a while to lose the muscle memory.

But I have no desire to go back.