[whatwg] text/html for html and xhtml (Was: Supporting MathML and SVG in text/html, and related topics)

Wed Apr 16 22:28:49 PDT 2008

William F Hammond wrote:
> The experiment begun around 2001 of "punishing" bad
> documents in application/xhtml+xml seems to have led to that mime type
> not being much used.

That has more to do with the fact that it wasn't supported in browsers 
used by 90+% of users for a number of years.

> So user agents need to learn how to recognize the good and the bad
> in both mimetypes.

Recognize and do what with it?

> Otherwise you have Gresham's Law: the bad documents will drive out the
> good.

Perhaps you should clearly state your definitions of "bad" and "good" in 
this case?  I'd also like to know, given those definitions, why it's bad 
for the "bad" documents to drive out the "good", and how you think your 
proposal will prevent that from happening.

> If it has a preamble beginning with "^<?xml " or a sensible
> xhtml DOCTYPE declaration or a first element "<html xmlns=...>",
> then handle it as xhtml unless and until it proves to be non-compliant
> xhtml (e.g, not well-formed xml, unquoted attributes, munged handling
> of xml namespaces, ...).  At the point it proves to be bad xhtml reload
> it and treat it as "regular" html.

What's the benefit?  This seems to give the worst of both worlds, as 
well as a poor user experience.

> So most bogus xhtml will then be 1 or 2 seconds slower than good xhtml.
> Astute content providers will notice that and then do something about it.
> It provides a feedback mechanism for making the web become better.

In the meantime, it punishes the users for things outside their control 
by degrading their user experience.  It also provides a competitive 
advantage to UAs who ignore your proposal.

Sounds like an unstable equilibrium to me, even if attainable.

-Boris