Re: [xml-dev] XHTML 5 and validation

[Jesper Tverskov <jesper.tverskov@gmail.com>]

OK David and Jirka, at least we are getting closer to a solution.

It turns out, that all what I have said so far is true for W3C Markup
Validator. But Validator.nu has some options you can use to preset it
to use the XHTML5 schema, but still it does not allow to validate my
XHTML5 document when sent with "text/html" unless I also check the box
"Be lax about HTTP Content-Type".

I guess that the above can be used both when we want to validate
XHTML5 using mimetype "text/html" for convenience (when I upload my
document to my webserver I will use mimetype "application/xhtml+xml"),
and also when we want to use well-formed HTML5 and lower-case for
element and attribute names to be served with mimetype "text/html" to
the browsers that don't understand "application/xhtml+xml" (today only
<=IE8).

But somehow I feel I am I right also when it comes to Validator.nu
(morally speaking). For years and implemented all over the place, we
have been used to get the validation we expect in one step. In Opera I
use Ctrl+Alt-Shift-U. We are not going to get validation in one step
with XHTML5 for many years to come in very many editors and tools. We
cannot even use the W3C Markup Validator at the moment but must find
validators like Validator.nu and experiment with its settings.

Some might even need a tutorial or help at this mailing list!

This is not good news for XHTML5. Validation for HTML5 on the other
hand works as expected right out of the box. This is a huge
disadvantage for XHTML5, could even be enough to kill it even as a
minority position.

A solution could be to let Validators accept the document as XHTML5 if
the XML declaration is used before the DOCTYPE. The validator could
then give a warning if mimetype "application/xhtml+xml" or similar is
not used. And in XML Editors I feel that it is important that
validation of XHTML5 is right out of the box as users would expect it
to work.

Ps 1)
Very nice with the XHTML5 preset in Validator.nu. It is first time I
have seen a link to the schema. Schematron! Is that the way it is
going to be, no DTD or XML Schema?

Ps 2)
And thanks for the link to "Polyglot Markup: HTML-Compatible XHTML
Documents, W3C Working Draft 05 April 2011. A whole Recommendation!

Cheers,
Jesper Tverskov
http://www.xmlplease.com