问题
I am marking up my content with schema.org microformats and am wondering about the itemscope attribute. The example given on http://schema.org/docs/gs.html is
<div itemscope itemtype="http://schema.org/Movie">
Is this valid HTML5? I thought attributes needed values, something like
<div itemscope="itemscope" itemtype="http://schema.org/Movie">
回答1:
It's a boolean attribute, which is valid HTML5.
If the attribute is present, its value must either be the empty string or a value that is an ASCII case-insensitive match for the attribute's canonical name, with no leading or trailing whitespace.
回答2:
If you want to produce valid XHTML5 (as opposed to HTML5 per se, which does not need to be well-formed XML), then @itemscope will need a value. Per the specs for boolean attributes linked by zzzzBov, to be valid XHTML 5 it will need to be one or the other of empty string or the attribute name, i.e. either <div itemscope=""> or <div itemscope="itemscope">
回答3:
As zzzBov said, it is valid HTML5.
Same thing with input fields and other types of content:
<input type="text" value="Text goes here" disabled>
Instead of disabled="disabled", HTML5 reads this as true because disabled is present.
回答4:
Simple answer - <div itemscope itemtype="http://schema.org/Movie"> is correct.
Example usage
Spec on itemscope
来源：https://stackoverflow.com/questions/10175342/html5-valid-itemscope