Can I add Microdata from HTML5 to a XHTML Strict site and still be compliant?
I've got a site coded in XHTML 1.0 Strict. I want to use the new Microdata to add breadcrumbs to my site (so Google will understand them).
My old non-microdata marked-up breadcrumbs look like this:
<ul>
<li><a href="...">Level 1</a></li>
<li><a href="...">Level 2</a></li>
<li><a href="...">Level 3</a></li>
</ul>
According to Google, to markup breadcrumbs using Microdata, you extend the above code like this:
<ul>
<li itemscope itemtype="http://data-vocabulary.org/Breadcrumb">
<a href="..." itemprop="url">
<span itemprop="title">Level 1</span>
</a>
</li>
...
</ul>
But this is not valid XHTML 1.0 Strict.
What should I do?
Should I ignore the validation conflicts?
Should I write itemscope="itemscope" instead of just itemscope (this would be valid XML, but still not valid XHTML)?
Should I change the Doctype to be HTML5 instead of XHTML 1.0 Strict?
I want this to work all the way back to IE6!
Please advice :)
Answer
Yes, if you wanted to use itemscope in XHTML, you would need to write itemscope="itemscope" and use XHTML5 (same DOCTYPE as HTML5, but XML syntax).
itemscope is not included in W3 HTML5, but present in WHATWG's version, so validation may continue to be a difficulty. There seems to be quite some political argument on this issue, which I haven't been following as it looks fairly tedious.
For the moment, if you want to use breadcrumb annotations in a finalised, validatable document format, you could use RDFa instead: the alternative (but older) proposal, which the argument is all about, and use the existing doctype:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML+RDFa 1.0//EN" "http://www.w3.org/MarkUp/DTD/xhtml-rdfa-1.dtd">