4 ms·
HTML4 was the last of "HTML-is-an-SGML-application" (that was the terminology when you define a document type with a SGML DTD) attempt before XHTML 1.0 came out
by necovek 4y ago
HTML4 was the last of "HTML-is-an-SGML-application" (that was the terminology when you define a document type with a SGML DTD) attempt before XHTML 1.0 came out.
SGML is what allows implicit closing tags, for instance.
Of course, even XHTML failed because it was too strict and browsers couldn't trust websites with following it to the letter, so we ended up with HTML as of today: clearly coming out of both, but not really either of them anymore.