[Bug 9964] New: Namespaces section should be more explicit + touch the extensibility problem


           Summary: Namespaces section should be more explicit + touch the
                    extensibility problem
           Product: HTML WG
           Version: unspecified
          Platform: All
               URL: http://dev.w3.org/html5/html-xhtml-author-guide/html-x
        OS/Version: All
            Status: NEW
          Severity: normal
          Priority: P2
         Component: HTML/XHTML Compatibility Authoring Guide (ed: Eliot
        AssignedTo: eliotgra@microsoft.com
        ReportedBy: xn--mlform-iua@xn--mlform-iua.no
         QAContact: public-html-bugzilla@w3.org
                CC: mike@w3.org, public-html@w3.org,

I suggest replace the current text on namespaces with the following.
(Justification below):

5. Namespaces

5.1 Element level namespaces

HTML5 introduces undeclared (native) default namespaces for the root HTML
element <html>, the root SVG element <svg> and the root MathML element <math>.
For XML-compatibility, polyglot markup REQUIRES these default namespaces to be

<html xmlns="http://www.w3.org/1999/xhtml">
 <svg xmlns="http://www.w3.org/2000/svg">
<math xmlns="http://www.w3.org/1998/Math/MathML">

Becuase HTML5 does not natively support it, the declaring of any other default
or prefixed element namespace is not natively supported in polyglot markup.

5.2 Attribute level namespaces
HTML5 introduces undeclared (native) support for attributes in the XLink
namespace and with the prefix <code>xlink:</code>. For XML-compatibility,
polyglot markup REQUIRES that the XLink namespace is declared once on the HTML
root element <html>, or once on the foreign element where is used — <svg> or

5.3 Attributes with the <code>xml:</code> or <code>xmlns:</code> prefix
HTML5 also allows the prefixed XML attributes base (xml:base), lang (xml:lang),
space (xml:space) and xlink (xmlns:xlink). Declaring the namespace of xml
prefix and the xmlns: prefix  is forbidden by XML.

5.4 Additional namespaces 
Other applicable specifications for XML and HTML may extend the possibility for
declaring namespaces in polyglot markup – in particular at attribute level
and attribute content level.  

JUSTIFICATION: The suggested text solves the following problems

(1) The old text is unclear, at least to me as non-native English reader. For
example to say that ]]The <html> element uses the namespace declaration "*"[[
is not perefectly clear since I am not used to hear that an element "*uses* the
namespaces declaration". And, even HTML5 "uses namespaces" - exepct that they
are not declared.

(2) I feel the text should be a bit more helpful and direct. The sectioning of
this section helps doing that, I hope.

(3) Sam Ruby asked, when Facebook introduced their OpenGraph protocol: "does
this affect the polyglot spec?" (Lots of the other comments seemd to take it
for granted.) And does it? What about the RDFa in HTML, how does it affect the
polyglot spec? My answer: The polyglot spec should in my view be very open to
RDFa. On the other side, what is the extension point? Answer: Same as in HTML5
= applicable specifications.

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Received on Monday, 21 June 2010 01:28:29 UTC