Namespaces in XML and XHTML

james anderson James.Anderson at
Fri Sep 10 07:52:17 BST 1999

Jon Bosak wrote:
> ...
> ------------------------------
> What are namespaces all about?
> ------------------------------
> Namespaces are about unique identification; they are not about
> meaning.  Identification is necessary to the establishment of meaning,
> but it does not constitute meaning in itself.
> [followed by a long discussion to the point that namespaces govern identity in the
>  encoding and decoding process only and leading to the following conclusions: ]
> -------------------------------------
> Should XHTML use multiple namespaces?
> -------------------------------------
> ...
>  - The main argument for specifying three namespaces for XHTML rests
>    on the assumption that there is a one-to-one association between
>    namespaces and schemas.  This is not true.

as established above, it is also insignificant.

>  - A second argument for specifying three namespaces is that it's
>    intended to indicate that XHTML actually specifies three different
>    tag languages and that <h2> in one of these languages means
>    something basically different from <h2> in the other two.  In my
>    opinion, <h2> means basically the same thing in all three
>    versions. ...
>    ...  If the HTML WG decides to maintain the position that
>    XHTML is defining three different languages, then it should be
>    ready to explain how an <h2> in one would materially differ in
>    meaning from an <h2> in another, "meaning" here being expressed in
>    terms of the intention of the person who causes elements to have
>    the type "h2."

which is also, as established above, insignificant.

>  - Another way of making what I believe to be essentially the same
>    point is that distinctions between a strict <h2> and a
>    transitional <h2> are not reflected in actual machine processing
>    outside of validation.

which decides the issue. as the namespaces are about unambiguously identifying
the encoded specifications for the validation, it is appropriate to make
adequate distinctions.
? is it specified somewhere that the various XHTML forms will never appear in
the same document?

>  - If XHTML really is several languages and the similarly named
>    elements of those languages really are different from each other,
>    then those different languages are going to require different HTML
>    DOMs.

i don't understand this one: if the variants are in different namespaces, then
elements of each could well be mixed in the same dom instance. isn't that the
point of the whole thing?

xml-dev: A list for W3C XML Developers. To post, mailto:xml-dev at
Archived as: and on CD-ROM/ISBN 981-02-3594-1
To (un)subscribe, mailto:majordomo at the following message;
(un)subscribe xml-dev
To subscribe to the digests, mailto:majordomo at the following message;
subscribe xml-dev-digest
List coordinator, Henry Rzepa (mailto:rzepa at

More information about the Xml-dev mailing list