The following is a snippet to get isDefaultNamespace() supported across other browsers.
Note that all Gecko-based browsers (including Firefox) support Node.isDefaultNamespace. This function is not necessary for Gecko-based browsers (though the function will quickly return the standard value for Mozilla browsers).
// https://www.w3.org/TR/DOM-Level-3-Core/core.html#Node3-isDefaultNamespace
// https://www.w3.org/TR/DOM-Level-3-Core/namespaces-algorithms.html#isDefaultNamespaceAlgo
function isDefaultNamespace(node, namespaceURI) {
if (node.isDefaultNamespace) {
return node.isDefaultNamespace(namespaceURI);
}
switch (node.nodeType) {
case 1: // ELEMENT_NODE
if (!node.prefix) {
return (node.namespaceURI === namespaceURI);
}
if (node.attributes.length) {
for (var i=0; i < node.attributes.length; i++) {
var att = node.attributes[i];
if (att.localName === 'xmlns') {
return att.value === namespaceURI;
}
}
}
if (node.parentNode) {
// EntityReferences may have to be skipped to get to it
return isDefaultNamespace(node.parentNode, namespaceURI);
}
else {
return false; // unknown;
}
case 9: // DOCUMENT_NODE
return isDefaultNamespace(node.documentElement, namespaceURI);
case 6: // ENTITY_NODE
case 12: // NOTATION_NODE
case 10: // DOCUMENT_TYPE_NODE
case 11: // DOCUMENT_FRAGMENT_NODE
return false; // unknown
case 2: // ATTRIBUTE_NODE:
if (node.ownerElement ) {
return isDefaultNamespace(node.ownerElement , namespaceURI);
}
else {
return false; // unknown
}
default:
if (node.parentNode) {
// EntityReferences may have to be skipped to get to it
return isDefaultNamespace(node.parentNode, namespaceURI);
}
else {
return false; // unknown
}
}
}