[whatwg] text/html flavor conformance checkers and <foo />

Olav Junker Kjær olav at olav.dk
Tue Apr 26 07:18:11 PDT 2005

James Graham wrote:
> Is there a good reason that <foo /> cannot be valid HTML5? Any parser 
> which doesn't support <foo /> also doesn't support much of the web 
> content produced in the last 2 years. In this case a conformance checker 
> could emit a warning (maybe only a strict warning) since it's not 
> impossible that people will expect HTML5 to work in a parser that's 
> incompatible with real-world HTML4.

A conformance checker should check conformance to the spec, not 
conformance to the behavior of actual UA's. But new specs should 
(arguable) be aligned with the behavior of actual UA's if they are to be 
backwards compatible.

There have been discussions about redefining the low-level parsing of 
HTML to bring it more in alignment with how current UA's works. If we 
want XHTML 1.0 to be legal HTML, it would make sense to allow the 
trailing slash in empty elements. That way, you could legally server the 
same content as both HTML and XHTML. (You can do that now, but it won't 
validate as HTML which is a drag. If you want to be able to serve the 
same content as both HTML and XHTML, you would want to make sure that it 
validates as both HTML and XHTML.)

Olav Junker Kjær

More information about the whatwg mailing list