[whatwg] Custom microdata handling added to HTML5 spec

Manu Sporny msporny at digitalbazaar.com
Sun May 10 15:12:53 PDT 2009

Shelley Powers wrote:
> Since a new section detailing HTML5's handling of custom microdata  has
> been added to the HTML5 spec
> http://dev.w3.org/html5/spec/Overview.html#microdata

I've only had a brief chance to look over the HTML5 Microdata spec, but
there is one big problem that overrides all of the other issues: The
HTML5 Microdata spec is in direct conflict with planned RDFa extensions
and will almost surely result in spurious triples being generated in
RDFa processors in the future.

We are currently working[1] on features to dynamically extending the
base set of reserved words and the set of pre-defined prefixes through a
mechanism called RDFa Profiles[2]. It is proposed that this mechanism
would allow authors to do this in their documents:

<div profile="http://example.org/myprofile.html"> ...
  <span property="description">A description for this page.</span>
  <span about="#me" property="name">Manu Sporny</span>

Note that 'description' and 'name' are not prefixed, but would be mapped
to a full URI in the document listed by @profile. This allows the ease
of Microformats-like markup but with all of the rigor of RDFa.

The HTML5 microdata proposal, as it stands right now, would create
numerous spurious triples if implemented and would violate the purpose
of @property as it is being developed in the RDFa community.

I'll have more comments on the microdata proposal based on the response
to this e-mail.

-- manu


Manu Sporny
President/CEO - Digital Bazaar, Inc.
blog: A Collaborative Distribution Model for Music

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