246604 - lookupNamespaceURI should probably be aware of xml prefix

Status: RESOLVED FIXED

(Core :: DOM: Core & HTML, defect)

Description

[Alex Vincent [:WeirdAl]]

The xml attribute prefix (for example, xml:lang) is fairly well-known, but 
Mozilla's lookupNamespaceURI method doesn't know about it.  Thus, to call 
aNode.lookupNamespaceURI("xml") would require that we explicitly declare the 
XML namespace.

We have a similar problem with aNode.lookupNamespaceURI("xmlns").  These are 
namespaces that are not going to change, and our DOM code shouldn't have to 
walk up the tree of nodes to find the right values... :)

Comment 1

[Boris Zbarsky [:bzbarsky]]

This is a performance enhancement, right?  Since "xmlns" and "xml" don't have
associated namespace URIs (due to the fact that they are not actually
namespaces)....

Comment 2

[Hixie (not reading bugmail)]

They do have associated namespace URIs.
   xml     http://www.w3.org/XML/1998/namespace
   xmlns   http://www.w3.org/2000/xmlns/
See: http://www.w3.org/TR/xml-names11/#xmlReserved

Comment 3

[Peter Van der Beken [:peterv]]

Note that the lookup algorithm is specified in
http://www.w3.org/TR/2004/REC-DOM-Level-3-Core-20040407/namespaces-algorithms.html#lookupNamespaceURIAlgo
That said, I never understood why that doesn't special-case xml and xmlns. DOM
Level 3 XPath ended up special-casing xml:
http://www.w3.org/TR/2004/NOTE-DOM-Level-3-XPath-20040226/xpath.html#XPathEvaluator-createNSResolver

Comment 4

[Alex Vincent [:WeirdAl]]

Attachment: special-case xml, xmlns prefixes

javascript:alert(document.lookupNamespaceURI("xml") + "\n" +
document.lookupNamespaceURI("xmlns"))

Comment 5

[Alex Vincent [:WeirdAl]]

fixed with checkin by timeless