Comment by bawolff

> XHTML. Have you ever read the parsing rules for HTML 5, where the semantics for bad HTML were formalized?

I actually have, and its not that bad.

If anything, the worst part is foreign content (svg, mathml) which have different rules more similar to xml but also not the same as xml.

Just as an aside, browsers still support xhtml, just serve with application/xhtml+xml mime type, and it all works including aggressive error checking. This is very much a situation where consumers are voting with their feet not browser vendors forcing a choice.