W3C home > Mailing lists > Public > public-html@w3.org > September 2012

Re: Clarification of "Extensibility" section (Was: Re: Getting HTML5 to Recommendation in 2014)

From: Jirka Kosek <jirka@kosek.cz>
Date: Thu, 20 Sep 2012 10:24:12 +0200
Message-ID: <505AD2AC.80900@kosek.cz>
To: Benjamin Hawkes-Lewis <bhawkeslewis@googlemail.com>
CC: Paul Cotton <Paul.Cotton@microsoft.com>, "public-html@w3.org" <public-html@w3.org>, Sam Ruby <rubys@intertwingly.net>, Maciej Stachowiak <mjs@apple.com>, "Janina Sajka <janina@rednote.net> (janina@rednote.net)" <janina@rednote.net>, Philippe Le Hegaret <plh@w3.org>, "Judy Brewer <jbrewer@w3.org> (jbrewer@w3.org)" <jbrewer@w3.org>, Jeff Jaffe <jeff@w3.org>, Tim Berners-Lee <timbl@w3.org>
On 20.9.2012 9:16, Benjamin Hawkes-Lewis wrote:

>> If this is intent then I see problem here -- documents using markup
>> defined in extension specifications will be non-conforming HTML5, they
>> should be as such marked by validator -- as a result extension
>> specification will not be true first-class citizens.
> "true first-class citizen" is loaded political jargon. Can you explain
> what you're talking about and why it matters in more straightforward
> language?

I see incosistency between the plan and current
extensibility/conformance clauses in the spec. The plan says that
extension specs are "first-class citizens" which in my understanding
means that features in them are part of conforming HTML5. On the other
hand current clause in HTML5 spec marks any attributes/elements defined
outside the core HTML5 spec as non-conforming.

If this is intent then it should be explicitly stated in the plan.

> Validators can support extension specs by including them as options
> for validating. (W3C validator already supports multiple
> specifications, including extension specificiations, e.g XHTML +
> RDFa.)

Given the possible number of extension specs I don't think this is
practical approach. It would be nightmare to maintain validator which
supports HTML5 + any combination of RDFa/MD/longdesc/meta generator/...

> If extension specs define a mechanism for detecting that a document is
> attempting conformance with the extension spec, then validators can
> even sniff which conformance criteria to use.

Uhm. Several people (including me) in past advocated for some sort of
versioning which can be used for specifying version of HTML5 and
conformance profile (set of extensions). Such approach was always very
strongly opposed by saying that browsers are supporting only one large
set of HTML related features and that using versioning and profiles
doesn't make sense here. So currently we don't have versioning mechanism
in HTML so it's hard to do sniffing unless you want scan complete
document for small bits of markup from some extension spec.

>> I think that this needs to be clarified. There is a large group of users
>> for which validoty/conformance matters and it should be clear what is
>> and what is not conforming HTML5 document.
> What text would you suggest to further clarify that your
> interpretation is correct?

I would be more happy if there is additional note saying something like:

Note: If the applicable specification defines additional attributes and
elements and they are used in a document, then such document is not
conforming HTML5 document. But it might be conforming to the applicable


  Jirka Kosek      e-mail: jirka@kosek.cz      http://xmlguru.cz
       Professional XML consulting and training services
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Received on Thursday, 20 September 2012 08:24:40 UTC

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