[whatwg] A Selector-based metadata proposal (was: Annotating structured data that HTML has no semantics for)

Toby Inkster mail at tobyinkster.co.uk
Wed May 20 09:56:43 PDT 2009

Given that one of the objections people cite with RDFa is complexity,
I'm not sure how this resolves things. It seems twice as complicated to
me. It creates fewer new attributes, true, but number of attributes
themselves don't create much confusion.

e.g. which is a simpler syntax:

<a href="http://foo.example.com/"


<a href="primary:url('http://foo.example.com/');

Stuffing multiple discrete pieces of information makes things harder for
parsing, harder for authoring tools and harder for authors. In RDFa,
each attribute performs a simple role - e.g. @rel specifies the
relationship between two resources; @rev specifies the relationship in
the reverse direction; @content allows you to override the
human-readable text of an element. Combining these into a single
attribute would not make things simpler.

Looking at the comparison given in section 4.2, CRDF appears to suffer
from several disadvantages compared to RDFa:

1. It's pretty ugly.

2. It's more verbose - though only by eleven bytes by my reckoning, so
this isn't a major issue.

3. It divorces the CURIE prefix definitions from the use of CURIEs in
the markup. This makes it more vulnerable to copy-paste problems. (As I
understand <link rel="metadata"> in the proposal, CURIE prefix
definitions can even be separated out into an external file. This
obscures them greatly and will certainly be a cause of copy-paste

4. It's ugly. I'm sorry, I just can't emphasise that enough.

Apart from the fact that *sometimes* RDFa involves a bit of repetition,
I don't see what problems this proposal is actually supposed to solve.

Repetition in practise seems to be something that page authors can deal
with. We don't provide a mechanism for setting the src or alt attributes
of multiple <img> elements which need to load the external image; or
setting the class attribute of the third cell in every row of a table.

So again, while I can see that this proposal would "work", in what way
is it supposed to be preferable to RDFa?

Toby Inkster <mail at tobyinkster.co.uk>

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