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Re: HTML WG Last Call Remarks to DOM 2 HTML

From: Steven Pemberton <steven.pemberton@cwi.nl>
Date: Thu, 18 Apr 2002 16:23:28 +0200
Message-ID: <009301c1e6e4$9d9600b0$86f5a8c0@srx41p>
To: "Philippe Le Hegaret" <plh@w3.org>, "HTML WG" <w3c-html-wg@w3.org>
Cc: "WWW DOM" <www-dom@w3.org>
Philippe, thank you for your remarks. Sorry for the delay in replying; my
fault entirely.

> > However, the group has striven from the
> > beginning to utilise generic XML technologies as much as possible, and
> > would prefer to see the W3C moving towards more generic solutions.
>
> XHTML 1.0 does not always use pure XML technologies such as XLink,
> XForms, or XML Base. Unfortunately, this forces us to include some
> "special" cases in the DOM API, including the DOM Level 3 Core
> itself. The DOM Working Group agrees that the future of a DOM API for
> XHTML is not inside the DOM Level 2 HTML API. On the other hand, XHTML
> 1.0 is still close enough to HTML 4.01. In order to facilitate the
> transition between HTML 4.01 and the XHTML world, users should to be
> able to address both documents using the same API. Also, some of the
> functionalities proposed by the DOM Level 2 are not accessible through
> the DOM Core API, due to their HTML/XHTML specificity.  Examples are the
> methods HTMLFormElement.submit(), or HTMLAnchorElement.focus(). Exposing
> the XHTML document through the DOM Core does not give access to the
> dynamic information such as HTMLInputElement.value either. We hope that
> W3C Working Groups will base their work on technologies such as XLink
> and/or XForms in the future. It will certainly facilitate the XML
> integration in the end-users applications.

We agree that XML technologies should be used whenever possible, and we have
always striven to do so. Our problem is not so much with things like submit,
but more with things like "HTMLBRElement" (just to pick one randomly). With
such specific bindings it means everytime we change our content models, the
HTML DOM potentially has to change. This is not good engineering.

If 'pure' XML DOM is considered insufficient for HTML use, we should
urgently be searching for solutions.

> Changes have been made to make clear that we are only base on HTML 4.01
> and XHTML 1.0 in sections 1.5, 1.6.1, and 1.6.3.

Thanks.

> Being able to infer convenience
> functions from the XML Schema is a more advanced topic. As of today, the
> WG is not planning to work on it and it is not clear if a technical
> solution is possible and in the scope of the W3C.

Since XHTML is an extensible family of languages, we see no alternative but
to find some solution that allows the DOM to be similarly extensible,
without recompiling the browser each time.

> > We would like some text explaining the relationship between the use of
> > the DOM and the relevant DTD for the document in question, and what
> > the processing consequences are when generating elements that are not
> > valid for the current document. In particular we would like to see
> > some explanation of "The text is parsed into the document's structure
> > model" in |HTMLDocument.write| and |writeln|.
>
> The relations between the DTD of the document and its DOM representation
> are not defined in the DOM API. In other world, neither the DOM Core API
> or the DOM HTML API are defined to be validating API and therefore they
> permit any kind of child insertion at any point. Validation is in the
> scope of the DOM Level 3 Abstract Schemas specification. The sentence
> "The text is parsed into the document's structure model" has been
> removed from the document. We will encourage users to use the DOM Level
> 3 Load and Save API in the future.

I'm not sure if our issue has been solved here. I will need to see the new
text.

> > Please refer to HTML 4 (as a generic) or HTML 4.01 (as a particular);
> > HTML 4.0 has been superceded by HTML 4.01. Please use the HTML 4.01
> > recommendation <http://www.w3.org/TR/html401/> as the reference.
>
> Fixed, we are now using HTML 4.01.

Fine, thanks.

> > Mixture of semantics: |name| and |id|. The '|name|' attribute has zero
> > semantics in XHTML. So |HTMLCollection.namedItem| should /only/ search
> > for |id| attributes in XHTML, and ignore '|name|' attributes. For
> > XHTML, |HTMLDocument.getElementsByName| should only return form
> > controls with matching |name|.
>
> Fixed. We added wording to mark the difference between HTML and XHTML
> for those methods.

Fine.

> > Doubtful Convenience
> > We are not convinced that there is any convenience in certain methods:
> > |HTMLDocument.anchors|: /all/ elements with an |id| are anchors in
> > HTML 4 and XHTML; what is the convenience of only returning the |<a>|
> > elements? Furthermore, since the |name| attribute has no semantics in
> > XHTML, the returned set should /always/ be empty for XHTML documents.
>
> Even if the name attribute has no semantic in XHTML 1.0, it is still
> part of this language. HTMLDocuments.anchors is kept in the DOM Level 2
> HTML API for backward compatibility reason. We added the following
> sentence:
>
> "The attribute name was deprecated in XHTML 1.0, therefore it is
> recommend to not use this attribute for XHTML 1.0 documents. Users
> should prefer the iterator mechanisms provided by DOM Level 2 Traversal
> and Range instead."

Well, the problem isn't that it is deprecated. The problem is that if you
use it, it has no effect. People *should* use the name attribute if their
documents are to be compatible with HTML UAs. If the aim of the HTML DOM2 is
to aid this compatibility, then this should be taken into account.

> > Since |<object>| is the recommended method for including images in a
> > document, what is the convenience of |HTMLDocument.images| only
> > returning |<img>| elements?
>
> The reason is backward compatiblity since this attribute is supported by
> both IE3.0 and NS3.0. However, since as the HTML WG mentioned, we was
> added to the description:
>
> "Note: As suggested by [HTML4.0], to include images, authors may use the
> OBJECT element or the IMG element. Therefore, it is recommended not to
> use this attribute to find the images in the document but
> getElementsByTagName with HTML 4.0 or getElementsByTagNameNS with XHTML
> 1.0."

s/HTML4.0/HTML4.01/
s/attribute/method/ I suppose.

It's not clear how the DOM2 HTML is aiding compatibility here if you have to
use different calls for the same purpose.

> > Textual issue
> > 1.6.2 suggests that there is some general naming technique applied,
> > and yet it seems only to apply to |htmlFor|, and not, for instance, to
> > |Element.className|, which according to 1.6.2 should be called
> > |h||tmlClass|.
>
> Again, for backward compatibility with IE3 and NS3, the name cannot be
> renamed.

OK, but then the text that says there is a general naming mechanism isn't
true: you only use that mechanism for a single name. You may as well say
that instead.

Best wishes,

Steven Pemberton
Received on Thursday, 18 April 2002 10:23:39 GMT

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