[whatwg] text/html for html and xhtml

Boris Zbarsky bzbarsky at MIT.EDU
Sun Apr 20 20:03:22 PDT 2008

William F Hammond wrote:
> 1.  Many search engines appear not to look at application/xhtml+xml.

That seems like a much simpler thing to fix in search engines than in 
the specification and UAs, to be honest.  I don't see this as a 
compelling reason to add complexity to the parsing model.

> 2.  Many content providers have reported that they are stranded,
>     i.e., their contractors who receive the content by "upload" for
>     subsequent placement under the eye of an http server do not
>     support application/xhtml+xml.

This is the argument for any type of content-type sniffing, no?  By this 
argument, why bother with MIME types at all?

> (And, of course, "text/xml" and "application/xml" are non-specific
> mimetypes for which there is no base namespace.  They are sane content
> channels for web browsers only when display is entirely controlled
> with something like CSS.)

Uh...  Have you tested this?  As I recall there are no major 
layout/rendering differences in Gecko, Opera, and Safari between an 
XHTML document sent as application/xhtml+xml and one sent as 
application/xml.  In both cases, it needs to have the XHTML namespace on 
all the nodes to be handled "correctly".  There are differences in terms 
of the DOM: the document doesn't necessarily implement the HTMLDocument 
interface.  HTML5 proposes to change that so that all Documents 
implement HTMLDocument if the UA supports HTMLDocument at all.  At that 
point it really won't matter whether XHTML is served as 
application/xhtml+xml from a DOM point of view.  There might be a new 
behavior difference introduced if the <body> background special-casing 
in CSS is extended to apply to application/xhtml+xml like it applies to 
text/html now.  But I'd hardly call application/xml delivery of XHTML 
"insane" now, and even less so after the HTMLDocument change is made.

If you're talking about UAs other than those three that support 
application/xhtml+xml, I'll admit to not knowing what the situation is 
with those.



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