Sam Ruby wrote:
Steven Pemberton wrote:
> The much-maligned Appendic C guidelines of XHTML1 were only there to
> give some hints on how to do this.
If it was much maligned, then perhaps we should consider a different
approach.
I agree.
> The upshot of this is that xmlns attributes will remain in the
DOM. This
> is good. And it is all we need.
I would actually make that statement stronger. HTML 5 requires that
attributes whose names begin with "xmlns:" be placed in the DOM in a
certain way.
What you say is true for all practical purposes when talking about
"the DOM" in browsers. It's not necessarily true in practice and per
spec for all kinds of things called "the DOM".
The public DOM API is required to throw when setting an attribute
whose namespace is null and whose local name is "xmlns:foo":
NAMESPACE_ERR: Raised if the qualifiedName is malformed per the
Namespaces in XML specification, if the qualifiedName has a prefix
and the namespaceURI is null, if the qualifiedName has a
prefix that is "xml" and the namespaceURI is different from "http://www.w3.org/XML/1998/namespace
", if the qualifiedName or its prefix is "xmlns" and the
namespaceURI is different from "http://www.w3.org/2000/xmlns/";, or
if the namespaceURI is "http://www.w3.org/2000/xmlns/"; and neither
the qualifiedName nor its prefix is "xmlns".
http://www.w3.org/TR/DOM-Level-3-Core/core.html#ID-ElSetAttrNS
Therefore, to comply with the HTML 5 parsing spec, the parser needs a
back door to the DOM. For example, if you set the html5.enable pref to
true in a recent nightly build of Firefox trunk, you get a parser that
uses such a back door.
The Validator.nu HTML Parser exposes the Java DOM API outside
browsers. It builds the tree using the public API, because it uses the
JDK/JAXP DOM implementation and the JDK/JAXP doesn't specify a back
door.
To address situations like this, HTML 5 licenses the parser to drop
those attributes, which is what the Validator.nu HTML Parser does by
default when used with the JAXP DOM:
If the XML API doesn't support attributes in no namespace that are
named "xmlns", attributes whose names start with "xmlns:", or
attributes in the XMLNS namespace, then the tool may drop such
attributes.
http://www.whatwg.org/specs/web-apps/current-work/#coercing-an-html-dom-into-an-infoset
For server-side use, it seems unwise to rely on things that need to be
mangled in order to make off-the-shelf XML tree implementations not
throw.
--
Henri Sivonen
hsivo...@iki.fi
http://hsivonen.iki.fi/
