alt Hacker News> I never understood why the more strict rules of XML for HTML never took off
Internet Explorer failing to support XHTML at all (which also forced everyone to serve XHTML with the HTML media type and avoid incompatible syntaxes like self-closing <script />), Firefox at first failing to support progressive rendering of XHTML, a dearth of tooling to emit well-formed XHTML (remember, those were the days of PHP emitting markup by string concatenation) and the resulting fear of pages entirely failing to render (the so-called Yellow Screen of Death), and a side helping of the WHATWG cartel^W organization declaring XHTML "obsolete". It probably didn't help that XHTML did not offer any new features over tag-soup HTML syntax.
I think most of those are actually no longer relevant, so I still kind of hope that XHTML could have a resurgence, and that the tag-soup syntax could be finally discarded. It's long overdue.
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> It probably didn't help that XHTML did not offer any new features over tag-soup HTML syntax.
Well, this is not entirely true: XML namespaces enabled attaching arbitrary data to XHTML elements in a much more elegant, orthogonal way than the half-assed solution HTML5 ended up with (the data-* attribute set), and embedding other XML applications like XForms, SVG and MathML (though I am not sure how widely supported this was at the time; some of this was backported into HTML5 anyway, in a way that later led to CVEs). But this is rather niche.
I was there, Gandalf. I was there 30 years ago. I was there when the strength of men failed.
Netscape started this. NCSA was in favor of XML style rules over SGML, but Netscape embraced SGML leniency fully and several tools of that era generated web pages that only rendered properly in Netscape. So people voted with their feet and went to the panderers. If I had a dollar for every time someone told me, “well it works in Netscape” I’d be retired by now.
Emitting correct XHTML was not that hard. The biggest problem was that browsers supported plugins that could corrupt whole page. If you created XHTML webpage you had to handle bug reports caused by poorly written plugins.
What I never understood was why, for HTML specifically, syntax errors are such a fundamental unsolvable problem that it's essential that browsers accept bad content.
Meanwhile, in any other formal language (including JS and CSS!), the standard assumption is that syntax errors are fatal, the responsibility for fixing lies with the page author, but also that fixing those errors is not a difficult problem.
Why is this a problem for HTML - and only HTML?