Question

I have a XML file like this

<a:books xmlns:a="ans">
    <a:book>
        <a:id> 1 </a:id>
        <a:title>The first book</a:title>
    </a:book>
</a:books>

By default, IE recognizes the a prefixes from the xml itself when I do a XPath query on it

x.selectNodes('//a:book').length  //gives 1, as desired

But if I tell it to use the XPath selection language to go along with the other browsers then it stops recognizing the prefixes used in the original XML.

x.setProperty('SelectionLanguage', 'XPath') 
x.selectNodes('//a:book').length 
//throws an error: "Referência a um prefixo de espaço para nome não declarado: 'a'." 
// I would translate it as "reference to an undeclared namespace prefix".

I know I can use x.setProperty('SelectionNamespaces', "xmlns:a='ans'") to stop the error but is there a way to programatically get the a->ans relation, like I can by using x.createNSResolver(x) in the other browsers?

Answer 1

You would need to access any namespace declaration attributes in the DOM and that way infer the prefix->namespace URI bindings yourself, MSXML (which IE uses) does not have any method like createNSResolver.

[edit]
Here is some sample code:

function getPrefixNamespaceBindings(element) {
  var bindings = {};
  for (var i = 0,
       attributes = element.attributes,
       l = attributes.length;
       i < l;
       i++)
  {
    if (attributes[i].prefix === 'xmlns')
    {
      bindings[attributes[i].nodeName.substring(attributes[i].nodeName.indexOf(':') + 1)] = attributes[i].nodeValue;
     }
  }
  return bindings;
}

var doc = new ActiveXObject('Msxml2.DOMDocument.6.0');
doc.loadXML('<xhtml:html xmlns:xhtml="http://www.w3.org/1999/xhtml" xmlns:svg="http://www.w3.org/2000/svg" id="root" xml:lang="en">...</xhtml:html>');

var bindings = getPrefixNamespaceBindings(doc.documentElement);
for (var prefix in bindings) {
  document.body.appendChild(document.createTextNode(prefix + '="' + bindings[prefix] + '" '));
}