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Re: Is XHTML 1.0 2nd ed. Section 4.3 really informative?

From: William F. Hammond <hammond@csc.albany.edu>
Date: 23 Dec 2001 09:28:22 -0500
To: ITO Tsuyoshi <tsuyoshi@is.s.u-tokyo.ac.jp>
Cc: www-html@w3.org
Message-ID: <i7d71657uh.fsf@pluto.math.albany.edu>
I don't see a need for change in XHTML 1.0 (SE) on this matter.

Let me go through what you wrote in reverse order:

> In addition, if the intent of Section 4 is to explain by examples what
> are Conforming XHTML Documents and what are not, I think the sentence

No, that is not the intent of section 4.

The title of section 4 (which is informative) is:
"Differences with HTML 4" .

> If that restriction is not a necessary condition for Conforming XHTML
> Documents but merely a suggestion for them to be compatible with
> existing HTML parsers, the word ``must'' in the sentence of Section
> 4.3 which I quoted before might be confusing:
> > All elements other than those declared in the DTD as EMPTY must have
> > an end tag.

It is a requirement; "must" is correct.

> > ITO Tsuyoshi <tsuyoshi@is.s.u-tokyo.ac.jp> wrote:
> > > To me, it is natural to forbid shorthand representation such as
> > > ``<span />'', because HTML 4.01 parsers might regard it as the
> > > beginning of an element, look for the corresponding end tag and get

A user agent that does _correct_ parsing would never confuse HTML 4.01
with any form of XHTML.  Most old widely distributed "browser class"
user agents, however, do what is casually called tag soup parsing
where little, if any, attention is given to a document type
declaration because such agents handle "text/html" objects as objects
marked up with a known vocabulary.  (There is defined behavior for
unknown vocabulary in such objects.)

Please note further that writing

     "De facto empty bold tags written this way (<b />) are
      legal but unwise."

in XHTML is very likely to confuse a "tag soup" agent.  The use of
such markup is very unwise in XHTML.

[ IMHO it was a bad choice in the design of XML not to provide
  syntactic delineation of defined-empty elements.  That is,
  the forms "<foo></foo>" and "<foo/>", which are equivalent,
  should not be equivalent.  The latter should have been necessary
  and sufficient for "foo" to be a defined-empty element.          ]

                                    -- Bill
Received on Sunday, 23 December 2001 09:28:31 UTC

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