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Re: foaf:sha1 property with img src=

From: Mark Birbeck <mark.birbeck@x-port.net>
Date: Mon, 31 Mar 2008 13:49:09 +0100
Message-ID: <a707f8300803310549j4e319cf0ncbff6bae048abac9@mail.gmail.com>
To: "Ivan Herman" <ivan@w3.org>
Cc: "Dan Brickley" <danbri@danbri.org>, "Daniel Renfer" <duck@kronkltd.net>, public-rdf-in-xhtml-tf@w3.org

Hi Ivan/Dan,

One of the big problems was that when viewed through an HTML parser,
your carefully constructed XHTML gets converted. Originally we allowed
things like this:

  <meta property="foaf:name">Ivan</meta>

but the problem is that as far as an HTML parser is concerned, there
are three sibling nodes here (<meta>, "Ivan", and </meta>), and not
one node with one child.

So although you could create a DTD or schema that would make this valid:

  <img><x></img>

it would be difficult to parse in HTML-only browsers like IE.

Which by the way, is why I tend to be conservative, and put the
closing tags on examples, just in case people cut-and-paste the
mark-up directly into their own documents. I usually write this:

  <span property="foaf:name" content="Ivan"></span>

rather than this:

  <span property="foaf:name" content="Ivan" />

Regards,

Mark

On 31/03/2008, Ivan Herman <ivan@w3.org> wrote:
>
>
>  Dan Brickley wrote:
>  > Ivan Herman wrote:
>  >>
>  >>
>  >> Daniel Renfer wrote:
>  >>>
>  >>> I ran into a similar issue when I was trying to convert my FOAF file
>  >>> into a prose XHTML+RDFa document. My problem was, how can I link to
>  >>> an image, but also specify the thumbnail version of that image?
>  >>>
>  >>> <#me>
>  >>>     foaf:depiction     <me.jpg>.
>  >>>
>  >>> <me.jpg>
>  >>>     foaf:thumbnail    <me-thumb.jpg>.
>  >>>
>  >>> It seems like the answer would be the same for both of them. It's a
>  >>> shame I can't just put a span inside of <img/>.
>  >>>
>  >>
>  >> I see Mark has already given an answer. Let me just add this: the fact
>  >> that <img> cannot have a child element was the source of huge
>  >> headaches for the Task Force: had it not been the case, a bunch of use
>  >> cases could have been treated much more easily...
>  >>
>  > Was there any consideration of defining conditional rules: "if used in a
>  > future version of HTML where <img> has child elements, then [blah
>  > blah...]" ?
>  >
>
>
> I think the TF just did not want to go there. The goal is to get RDFa
>  out of the door as soon as possible. There might be an RDFa 1.1, where
>  such issues can then be considered in a much more relaxed way...
>
>
>  Ivan
>
>
>  > Or perhaps that's too speculative. I've not check HTML5's thinking on
>  > this...
>  >
>  > Dan
>  >
>
>
> --
>
>  Ivan Herman, W3C Semantic Web Activity Lead
>  Home: http://www.w3.org/People/Ivan/
>  PGP Key: http://www.ivan-herman.net/pgpkey.html
>  FOAF: http://www.ivan-herman.net/foaf.rdf
>
>


-- 
  Mark Birbeck

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Received on Monday, 31 March 2008 12:49:46 GMT

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