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RE: empty metadata elements

From: Jon Hanna <jon@spin.ie>
Date: Tue, 11 Feb 2003 13:14:23 -0000
To: <w3c-wai-ig@w3.org>
Message-ID: <NDBBLCBLIMDOPKMOPHLHKEODENAA.jon@spin.ie>

> > Agreed. However in some cases there may be the possibility of
> > there being
> > several different values for the same property,
>
> Can you give an example Jon? I'm a bit confused because although
> many meta'tags' can have different values for content="" e.g.
> <meta name="DC.Subject" can have many different content values,
> surely the content is either null or it is not.  Or am I
> misunderstanding what you're saying?

Okay, me and my colleague Tony create a page:
<meta name="DC.Creator" content="Jon" />
<meta name="DC.Creator" content="Tony" />

Both of the statements made by those elements are correct. Whether it would
be better or worse to have used <meta name="DC.Creator" content="Jon and
Tony" /> can be debated on a few grounds, but whatever is best the example
above is (apparently) allowed. If one of those elements were removed it
wouldn't impact on the validity of the remaining one (since DC.Creator),
although certain false assumptions might be made (that either myself or Tony
was the only creator).

If we then add:

<meta name="DC.Creator" content="" /> then we have three statements about
the creator of the page, one of which is of no value.

If we then remove the first two, what does the remaining null statement
mean? It doesn't rule out the possibility of there being other DC.Creator
statements that *could* be made, and hence is essentially meaningless.

On the other hand if DC.Creator meant *the* creator rather than a creator
(it is meant to be the entity "primarily responsible for making the content
or resource, but that doesn't preclude that primary responsibility being
shared), then the meaning of null would differ.

> >...in which case
> > the strength
> > of the statement is weakened....
>
> That seems to imply that the action of creating the statement in
> the first place is a positive thing. I'm not arguing here, just
> seeking clarification. I actually like the idea of making the
> statement if it has the same sort of connotations as including a
> null value for the alt attribute.

Agreed. But the connotations differ according to the metadata property in
question.
For example an expiry date property *could* be given the semantics which
meant that a null value indicated the content wouldn't expire, or at least
had no planned expiration at present.

<meta /> is unfortunately a very loose syntax (<link /> is better, but still
lacking in comparison to some equivalents). I'm inclined to think that
beyond simple assertions of non-critical information the use of <meta /> is
flogging a dead horse.
Received on Tuesday, 11 February 2003 08:15:14 GMT

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