W3C home > Mailing lists > Public > public-rdf-in-xhtml-tf@w3.org > April 2007

Re: HREF attribute in elements other than A and LINK

From: Ivan Herman <ivan@w3.org>
Date: Tue, 17 Apr 2007 09:05:48 +0200
Message-ID: <462471CC.2010607@w3.org>
To: mark.birbeck@x-port.net
CC: RDFa <public-rdf-in-xhtml-tf@w3.org>
Mark,

with all due respect: I have the impression that this is a different
(albeit interesting!) discussion. The issue at hand for me is how to
achieve acceptance of RDFa in the current HTML 'climate', with the
current view of HTML. I do not think we can have any influence on the
'mental model' on HTML at the moment, if I look at the discussions
around HTML4 and HTML5. And *that* is what we are up against at the
moment in terms of acceptance. And hence my general approach: try to get
something that is most easily swallowable, so to say. Unless it is
*absolutely necessary* for our goals in RDFa, I would avoid unnecessary
discussions, and both questions asked by Ben (usage of href everywhere,
and the usage of meta/link in the body) would lead to those.


Ivan

Mark Birbeck wrote:
> 
> Hi Ivan,
> 
> I think that the reason there was some suggestion that having @href on
> an element should immediately mean that it was a 'navigable link', is
> because that's what it _seems_ to mean in HTML and that's what it
> _definitely_ means in XHTML 2. So based on this, it felt to some that
> if we were going to have @hrefs that _weren't_ navigable, we had
> somehow introduced an inconsistency.
> 
> However, as with all of these things, acceptance is largely based on
> creating mental models that everyone feels comfortable with, so the
> question is whether we can come up with a 'new' mental model that
> describes _both_ the old stuff and the new.
> 
> One way to do that would be to say that in HTML, what was going on was
> that @href was describing a *relationship* between one document and
> another, with @rel/@rev specifying the nature of that relationship.
> The presence of either an anchor tag (<a>) or an image map area
> (<area>) could further augment the use of that relationship, and allow
> the connection to the 'other document' to become _navigable_.
> 
> This seems to me a reasonable way of 'interpreting' HTML, although of
> course it's not something you'll find in the specification for 4.01.
> The argument is simply that, since not all uses of @href result in
> navigable links--<link> and <base> both use @href without necessarily
> giving navigable links--then we can already say that there is no
> reason to assume that allowing @href everywhere would introduce
> confusion, were links to be non-navigable.
> 
> (And of course the converse is true; there are certain values of @rel
> that will use @href in other ways, such as as a URL from which to
> retrieve stylesheets, and even as another kind of navigable link that
> is outside the main document, such as 'next', 'previous', and so on.
> In other words, @href on its own doesn't tell you enough to know how
> to handle the URL, merely that there is one.)
> 
> So, we can see that it's quite easy to create a model of HTML where
> @href has a dual purpose; the first is to be part of a definition of a
> relationship with another document, and the second is to define a
> 'parameter' to some functionality--the URL to navigate to on <a>, the
> stylesheet to load with <link>, and so on.
> 
> Now...XHTML 2 does of course go further, and say that any element with
> @href on is a navigable link. Although that's another 'mental model'
> that seems right from a semantic point of view (you don't tend to
> write a document that contains 'links', you tend to write documents
> that contain paragraphs, headings, sections, notes, etc.), I don't
> think that should influence our current discussion.
> 
> The reason I say that is that we're trying to build 'mental models'
> that both work within the confines of current technology, and allow us
> to provide a 'bridge' to the future. As you point out Ivan, current
> browsers are already programmed to ignore attributes they don't
> understand, so allowing @href everywhere is readily achievable.
> 
> And although it's not at all difficult to add code to parsers like
> Ben's bookmarklet, that will make all @hrefs clickable, I'm not
> convinced that this is the concern of RDFa, and we can leave that
> 'mental model' for XHTML 2 to sort out when the time comes.
> 
> Regards,
> 
> Mark
> 
> 
> On 16/04/07, Ivan Herman <ivan@w3.org> wrote:
>>
>>
>> Ben Adida wrote:
>> > 1) should we define the RDFa module to allow for HREF on any element?
>> >
>>
>> I would like to see strong RDFa use cases for this need.
>>
>> My trick on my home page was to use
>>
>> <a href="blabla" rev="..." style="display:none"> </a>
>>
>> which covered most of my needs:-) It is a bit ugly, but it works... (in
>> case one wants to add some RDF links here and there...)
>>
>> > 2) if so, should we ask XHTML1.1+RDFa-compliant agents to make these
>> > elements clickable.
>> >
>>
>> I would not expect that to happen, let us be realistic. In view of the
>> current mood around HTML and HTML agents, the maximum we can expect is
>> that the HTML group would define a way to add attributes to the current
>> HTML elements that would not require any change on the HTML agents' core
>> behaviour (ignoring unknown attributes is already part of this
>> behaviour, I would expect). Anything more than that will simply not
>> happen in the coming years.
>>
>> On the other hand... you are right that 1) without 2) sounds bad. I
>> guess this is an argument against 1), too
>>
>> > A related issue is whether the XHTML1.1 RDFa module should allow LINK
>> > and META inside the body, where XHTML1.1 does not.
>> >
>>
>> Again, from a 'political' point of view, I think it is better not to go
>> there. HTML browsers might be much more prepared to accept (and ignore)
>> new attributes; I would expect much more push back on a change in the
>> content model.
>>
>> > Let's discuss!
>> >
>>
>> You mean: let the tempest begin!:-)
>>
>> Ivan
>>
>> > -Ben
>> >
>>
>> -- 
>>
>> Ivan Herman, W3C Semantic Web Activity Lead
>> URL: http://www.w3.org/People/Ivan/
>> PGP Key: http://www.cwi.nl/%7Eivan/AboutMe/pgpkey.html
>> FOAF: http://www.ivan-herman.net/foaf.rdf
>>
>>
> 
> 

-- 

Ivan Herman, W3C Semantic Web Activity Lead
URL: http://www.w3.org/People/Ivan/
PGP Key: http://www.cwi.nl/%7Eivan/AboutMe/pgpkey.html
FOAF: http://www.ivan-herman.net/foaf.rdf


Received on Tuesday, 17 April 2007 07:05:33 GMT

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