diff --git a/src/dom/document.zig b/src/dom/document.zig
index 23609600..b889169b 100644
--- a/src/dom/document.zig
+++ b/src/dom/document.zig
@@ -36,6 +36,11 @@ pub const Document = struct {
         return Element.toInterface(e);
     }
 
+    pub fn _createElementNS(self: *parser.Document, ns: []const u8, tag_name: []const u8) ElementUnion {
+        const e = parser.documentCreateElementNS(self, ns, tag_name);
+        return Element.toInterface(e);
+    }
+
     // We can't simply use libdom dom_document_get_elements_by_tag_name here.
     // Indeed, netsurf implemented a previous dom spec when
     // getElementsByTagName returned a NodeList.
diff --git a/src/netsurf.zig b/src/netsurf.zig
index 24bb1771..7052a0ac 100644
--- a/src/netsurf.zig
+++ b/src/netsurf.zig
@@ -752,6 +752,12 @@ pub inline fn documentCreateElement(doc: *Document, tag_name: []const u8) *Eleme
     return elem.?;
 }
 
+pub inline fn documentCreateElementNS(doc: *Document, ns: []const u8, tag_name: []const u8) *Element {
+    var elem: ?*Element = undefined;
+    _ = documentVtable(doc).dom_document_create_element_ns.?(doc, stringFromData(ns), stringFromData(tag_name), &elem);
+    return elem.?;
+}
+
 // DocumentHTML
 pub const DocumentHTML = c.dom_html_document;
 
diff --git a/tests/wpt/dom/nodes/Document-createElementNS.html b/tests/wpt/dom/nodes/Document-createElementNS.html
new file mode 100644
index 00000000..5ad81043
--- /dev/null
+++ b/tests/wpt/dom/nodes/Document-createElementNS.html
@@ -0,0 +1,224 @@
+<!DOCTYPE html>
+<meta charset=utf-8>
+<title>Document.createElementNS</title>
+<link rel=help href="https://dom.spec.whatwg.org/#dom-document-createelementns">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="Document-createElementNS.js"></script>
+<div id="log"></div>
+<iframe src="/common/dummy.xml"></iframe>
+<iframe src="/common/dummy.xhtml"></iframe>
+<script>
+var tests = createElementNS_tests.concat([
+  /* Arrays with three elements:
+   *   the namespace argument
+   *   the qualifiedName argument
+   *   the expected exception, or null if none
+   */
+  ["", "", "INVALID_CHARACTER_ERR"],
+  [null, "", "INVALID_CHARACTER_ERR"],
+  [undefined, "", "INVALID_CHARACTER_ERR"],
+  ["http://example.com/", null, null],
+  ["http://example.com/", "", "INVALID_CHARACTER_ERR"],
+  ["/", null, null],
+  ["/", "", "INVALID_CHARACTER_ERR"],
+  ["http://www.w3.org/XML/1998/namespace", null, null],
+  ["http://www.w3.org/XML/1998/namespace", "", "INVALID_CHARACTER_ERR"],
+  ["http://www.w3.org/2000/xmlns/", null, "NAMESPACE_ERR"],
+  ["http://www.w3.org/2000/xmlns/", "", "INVALID_CHARACTER_ERR"],
+  ["foo:", null, null],
+  ["foo:", "", "INVALID_CHARACTER_ERR"],
+])
+
+var xmlIframe = document.querySelector('[src="/common/dummy.xml"]');
+var xhtmlIframe = document.querySelector('[src="/common/dummy.xhtml"]');
+
+function runTest(t, i, desc) {
+  async_test(function(testObj) {
+    window.addEventListener("load", function() {
+      testObj.step(function() {
+        var doc;
+        if (desc == "HTML document") {
+          doc = document;
+        } else if (desc == "XML document") {
+          doc = xmlIframe.contentDocument;
+          // Make sure we're testing the right document
+          assert_equals(doc.documentElement.textContent, "Dummy XML document");
+        } else if (desc == "XHTML document") {
+          doc = xhtmlIframe.contentDocument;
+          assert_equals(doc.documentElement.textContent, "Dummy XHTML document");
+        }
+        var namespace = t[0], qualifiedName = t[1], expected = t[2]
+        if (expected != null) {
+          assert_throws_dom(expected, doc.defaultView.DOMException, function() {doc.createElementNS(namespace, qualifiedName) });
+        } else {
+          var element = doc.createElementNS(namespace, qualifiedName)
+          assert_not_equals(element, null)
+          assert_equals(element.nodeType, Node.ELEMENT_NODE)
+          assert_equals(element.nodeType, element.ELEMENT_NODE)
+          assert_equals(element.nodeValue, null)
+          assert_equals(element.ownerDocument, doc)
+          var qualified = String(qualifiedName), names = []
+          if (qualified.indexOf(":") >= 0) {
+            names = qualified.split(":", 2)
+          } else {
+            names = [null, qualified]
+          }
+          assert_equals(element.prefix, names[0])
+          assert_equals(element.localName, names[1])
+          assert_equals(element.tagName, qualified)
+          assert_equals(element.nodeName, qualified)
+          assert_equals(element.namespaceURI,
+                        namespace === undefined || namespace === "" ? null
+                                                                    : namespace)
+        }
+      });
+      testObj.done();
+    });
+  }, "createElementNS test in " + desc + ": " + t.map(format_value))
+}
+
+tests.forEach(function(t, i) {
+  runTest(t, i, "HTML document")
+  runTest(t, i, "XML document")
+  runTest(t, i, "XHTML document")
+})
+
+
+test(function() {
+  var HTMLNS = "http://www.w3.org/1999/xhtml";
+  var element = document.createElementNS(HTMLNS, "span");
+  assert_equals(element.namespaceURI, HTMLNS);
+  assert_equals(element.prefix, null);
+  assert_equals(element.localName, "span");
+  assert_equals(element.tagName, "SPAN");
+  assert_true(element instanceof Node, "Should be a Node");
+  assert_true(element instanceof Element, "Should be an Element");
+  assert_true(element instanceof HTMLElement, "Should be an HTMLElement");
+  assert_true(element instanceof HTMLSpanElement, "Should be an HTMLSpanElement");
+}, "Lower-case HTML element without a prefix");
+
+test(function() {
+  var HTMLNS = "http://www.w3.org/1999/xhtml";
+  var element = document.createElementNS(HTMLNS, "html:span");
+  assert_equals(element.namespaceURI, HTMLNS);
+  assert_equals(element.prefix, "html");
+  assert_equals(element.localName, "span");
+  assert_equals(element.tagName, "HTML:SPAN");
+  assert_true(element instanceof Node, "Should be a Node");
+  assert_true(element instanceof Element, "Should be an Element");
+  assert_true(element instanceof HTMLElement, "Should be an HTMLElement");
+  assert_true(element instanceof HTMLSpanElement, "Should be an HTMLSpanElement");
+}, "Lower-case HTML element with a prefix");
+
+test(function() {
+  var element = document.createElementNS("test", "span");
+  assert_equals(element.namespaceURI, "test");
+  assert_equals(element.prefix, null);
+  assert_equals(element.localName, "span");
+  assert_equals(element.tagName, "span");
+  assert_true(element instanceof Node, "Should be a Node");
+  assert_true(element instanceof Element, "Should be an Element");
+  assert_false(element instanceof HTMLElement, "Should not be an HTMLElement");
+  assert_false(element instanceof HTMLSpanElement, "Should not be an HTMLSpanElement");
+}, "Lower-case non-HTML element without a prefix");
+
+test(function() {
+  var element = document.createElementNS("test", "html:span");
+  assert_equals(element.namespaceURI, "test");
+  assert_equals(element.prefix, "html");
+  assert_equals(element.localName, "span");
+  assert_equals(element.tagName, "html:span");
+  assert_true(element instanceof Node, "Should be a Node");
+  assert_true(element instanceof Element, "Should be an Element");
+  assert_false(element instanceof HTMLElement, "Should not be an HTMLElement");
+  assert_false(element instanceof HTMLSpanElement, "Should not be an HTMLSpanElement");
+}, "Lower-case non-HTML element with a prefix");
+
+test(function() {
+  var HTMLNS = "http://www.w3.org/1999/xhtml";
+  var element = document.createElementNS(HTMLNS, "SPAN");
+  assert_equals(element.namespaceURI, HTMLNS);
+  assert_equals(element.prefix, null);
+  assert_equals(element.localName, "SPAN");
+  assert_equals(element.tagName, "SPAN");
+  assert_true(element instanceof Node, "Should be a Node");
+  assert_true(element instanceof Element, "Should be an Element");
+  assert_true(element instanceof HTMLElement, "Should be an HTMLElement");
+  assert_true(element instanceof HTMLUnknownElement, "Should be an HTMLUnknownElement");
+  assert_false(element instanceof HTMLSpanElement, "Should not be an HTMLSpanElement");
+}, "Upper-case HTML element without a prefix");
+
+test(function() {
+  var HTMLNS = "http://www.w3.org/1999/xhtml";
+  var element = document.createElementNS(HTMLNS, "html:SPAN");
+  assert_equals(element.namespaceURI, HTMLNS);
+  assert_equals(element.prefix, "html");
+  assert_equals(element.localName, "SPAN");
+  assert_equals(element.tagName, "HTML:SPAN");
+  assert_true(element instanceof Node, "Should be a Node");
+  assert_true(element instanceof Element, "Should be an Element");
+  assert_true(element instanceof HTMLElement, "Should be an HTMLElement");
+  assert_false(element instanceof HTMLSpanElement, "Should not be an HTMLSpanElement");
+}, "Upper-case HTML element with a prefix");
+
+test(function() {
+  var element = document.createElementNS("test", "SPAN");
+  assert_equals(element.namespaceURI, "test");
+  assert_equals(element.prefix, null);
+  assert_equals(element.localName, "SPAN");
+  assert_equals(element.tagName, "SPAN");
+  assert_true(element instanceof Node, "Should be a Node");
+  assert_true(element instanceof Element, "Should be an Element");
+  assert_false(element instanceof HTMLElement, "Should not be an HTMLElement");
+  assert_false(element instanceof HTMLSpanElement, "Should not be an HTMLSpanElement");
+}, "Upper-case non-HTML element without a prefix");
+
+test(function() {
+  var element = document.createElementNS("test", "html:SPAN");
+  assert_equals(element.namespaceURI, "test");
+  assert_equals(element.prefix, "html");
+  assert_equals(element.localName, "SPAN");
+  assert_equals(element.tagName, "html:SPAN");
+  assert_true(element instanceof Node, "Should be a Node");
+  assert_true(element instanceof Element, "Should be an Element");
+  assert_false(element instanceof HTMLElement, "Should not be an HTMLElement");
+  assert_false(element instanceof HTMLSpanElement, "Should not be an HTMLSpanElement");
+}, "Upper-case non-HTML element with a prefix");
+
+test(function() {
+  var element = document.createElementNS(null, "span");
+  assert_equals(element.namespaceURI, null);
+  assert_equals(element.prefix, null);
+  assert_equals(element.localName, "span");
+  assert_equals(element.tagName, "span");
+  assert_true(element instanceof Node, "Should be a Node");
+  assert_true(element instanceof Element, "Should be an Element");
+  assert_false(element instanceof HTMLElement, "Should not be an HTMLElement");
+  assert_false(element instanceof HTMLSpanElement, "Should not be an HTMLSpanElement");
+}, "null namespace");
+
+test(function() {
+  var element = document.createElementNS(undefined, "span");
+  assert_equals(element.namespaceURI, null);
+  assert_equals(element.prefix, null);
+  assert_equals(element.localName, "span");
+  assert_equals(element.tagName, "span");
+  assert_true(element instanceof Node, "Should be a Node");
+  assert_true(element instanceof Element, "Should be an Element");
+  assert_false(element instanceof HTMLElement, "Should not be an HTMLElement");
+  assert_false(element instanceof HTMLSpanElement, "Should not be an HTMLSpanElement");
+}, "undefined namespace");
+
+test(function() {
+  var element = document.createElementNS("", "span");
+  assert_equals(element.namespaceURI, null);
+  assert_equals(element.prefix, null);
+  assert_equals(element.localName, "span");
+  assert_equals(element.tagName, "span");
+  assert_true(element instanceof Node, "Should be a Node");
+  assert_true(element instanceof Element, "Should be an Element");
+  assert_false(element instanceof HTMLElement, "Should not be an HTMLElement");
+  assert_false(element instanceof HTMLSpanElement, "Should not be an HTMLSpanElement");
+}, "empty string namespace");
+</script>
diff --git a/tests/wpt/dom/nodes/Document-createElementNS.js b/tests/wpt/dom/nodes/Document-createElementNS.js
new file mode 100644
index 00000000..2cf29485
--- /dev/null
+++ b/tests/wpt/dom/nodes/Document-createElementNS.js
@@ -0,0 +1,189 @@
+var createElementNS_tests = [
+  /* Arrays with three elements:
+   *   the namespace argument
+   *   the qualifiedName argument
+   *   the expected exception, or null if none
+   */
+  [null, null, null],
+  [null, undefined, null],
+  [null, "foo", null],
+  [null, "1foo", "INVALID_CHARACTER_ERR"],
+  [null, "f1oo", null],
+  [null, "foo1", null],
+  [null, "\u0BC6foo", null],
+  [null, "\u037Efoo", "INVALID_CHARACTER_ERR"],
+  [null, "}foo", "INVALID_CHARACTER_ERR"],
+  [null, "f}oo", "INVALID_CHARACTER_ERR"],
+  [null, "foo}", "INVALID_CHARACTER_ERR"],
+  [null, "\uFFFFfoo", "INVALID_CHARACTER_ERR"],
+  [null, "f\uFFFFoo", "INVALID_CHARACTER_ERR"],
+  [null, "foo\uFFFF", "INVALID_CHARACTER_ERR"],
+  [null, "<foo", "INVALID_CHARACTER_ERR"],
+  [null, "foo>", "INVALID_CHARACTER_ERR"],
+  [null, "<foo>", "INVALID_CHARACTER_ERR"],
+  [null, "f<oo", "INVALID_CHARACTER_ERR"],
+  [null, "^^", "INVALID_CHARACTER_ERR"],
+  [null, "fo o", "INVALID_CHARACTER_ERR"],
+  [null, "-foo", "INVALID_CHARACTER_ERR"],
+  [null, ".foo", "INVALID_CHARACTER_ERR"],
+  [null, ":foo", "INVALID_CHARACTER_ERR"],
+  [null, "f:oo", "NAMESPACE_ERR"],
+  [null, "foo:", "INVALID_CHARACTER_ERR"],
+  [null, "f:o:o", "INVALID_CHARACTER_ERR"],
+  [null, ":", "INVALID_CHARACTER_ERR"],
+  [null, "xml", null],
+  [null, "xmlns", "NAMESPACE_ERR"],
+  [null, "xmlfoo", null],
+  [null, "xml:foo", "NAMESPACE_ERR"],
+  [null, "xmlns:foo", "NAMESPACE_ERR"],
+  [null, "xmlfoo:bar", "NAMESPACE_ERR"],
+  [null, "null:xml", "NAMESPACE_ERR"],
+  ["", null, null],
+  ["", ":foo", "INVALID_CHARACTER_ERR"],
+  ["", "f:oo", "NAMESPACE_ERR"],
+  ["", "foo:", "INVALID_CHARACTER_ERR"],
+  [undefined, null, null],
+  [undefined, undefined, null],
+  [undefined, "foo", null],
+  [undefined, "1foo", "INVALID_CHARACTER_ERR"],
+  [undefined, "f1oo", null],
+  [undefined, "foo1", null],
+  [undefined, ":foo", "INVALID_CHARACTER_ERR"],
+  [undefined, "f:oo", "NAMESPACE_ERR"],
+  [undefined, "foo:", "INVALID_CHARACTER_ERR"],
+  [undefined, "f::oo", "INVALID_CHARACTER_ERR"],
+  [undefined, "xml", null],
+  [undefined, "xmlns", "NAMESPACE_ERR"],
+  [undefined, "xmlfoo", null],
+  [undefined, "xml:foo", "NAMESPACE_ERR"],
+  [undefined, "xmlns:foo", "NAMESPACE_ERR"],
+  [undefined, "xmlfoo:bar", "NAMESPACE_ERR"],
+  ["http://example.com/", "foo", null],
+  ["http://example.com/", "1foo", "INVALID_CHARACTER_ERR"],
+  ["http://example.com/", "<foo>", "INVALID_CHARACTER_ERR"],
+  ["http://example.com/", "fo<o", "INVALID_CHARACTER_ERR"],
+  ["http://example.com/", "-foo", "INVALID_CHARACTER_ERR"],
+  ["http://example.com/", ".foo", "INVALID_CHARACTER_ERR"],
+  ["http://example.com/", "f1oo", null],
+  ["http://example.com/", "foo1", null],
+  ["http://example.com/", ":foo", "INVALID_CHARACTER_ERR"],
+  ["http://example.com/", "f:oo", null],
+  ["http://example.com/", "f:o:o", "INVALID_CHARACTER_ERR"],
+  ["http://example.com/", "foo:", "INVALID_CHARACTER_ERR"],
+  ["http://example.com/", "f::oo", "INVALID_CHARACTER_ERR"],
+  ["http://example.com/", "a:0", "INVALID_CHARACTER_ERR"],
+  ["http://example.com/", "0:a", "INVALID_CHARACTER_ERR"],
+  ["http://example.com/", "a:_", null],
+  ["http://example.com/", "a:\u0BC6", null],
+  ["http://example.com/", "a:\u037E", "INVALID_CHARACTER_ERR"],
+  ["http://example.com/", "a:\u0300", "INVALID_CHARACTER_ERR"],
+  ["http://example.com/", "\u0BC6:a", null],
+  ["http://example.com/", "\u0300:a", "INVALID_CHARACTER_ERR"],
+  ["http://example.com/", "\u037E:a", "INVALID_CHARACTER_ERR"],
+  ["http://example.com/", "a:a\u0BC6", null],
+  ["http://example.com/", "a\u0BC6:a", null],
+  ["http://example.com/", "xml:test", "NAMESPACE_ERR"],
+  ["http://example.com/", "xmlns:test", "NAMESPACE_ERR"],
+  ["http://example.com/", "test:xmlns", null],
+  ["http://example.com/", "xmlns", "NAMESPACE_ERR"],
+  ["http://example.com/", "_:_", null],
+  ["http://example.com/", "_:h0", null],
+  ["http://example.com/", "_:test", null],
+  ["http://example.com/", "l_:_", null],
+  ["http://example.com/", "ns:_0", null],
+  ["http://example.com/", "ns:a0", null],
+  ["http://example.com/", "ns0:test", null],
+  ["http://example.com/", "a.b:c", null],
+  ["http://example.com/", "a-b:c", null],
+  ["http://example.com/", "xml", null],
+  ["http://example.com/", "XMLNS", null],
+  ["http://example.com/", "xmlfoo", null],
+  ["http://example.com/", "xml:foo", "NAMESPACE_ERR"],
+  ["http://example.com/", "XML:foo", null],
+  ["http://example.com/", "xmlns:foo", "NAMESPACE_ERR"],
+  ["http://example.com/", "XMLNS:foo", null],
+  ["http://example.com/", "xmlfoo:bar", null],
+  ["http://example.com/", "prefix::local", "INVALID_CHARACTER_ERR"],
+  ["http://example.com/", "namespaceURI:{", "INVALID_CHARACTER_ERR"],
+  ["http://example.com/", "namespaceURI:}", "INVALID_CHARACTER_ERR"],
+  ["http://example.com/", "namespaceURI:~", "INVALID_CHARACTER_ERR"],
+  ["http://example.com/", "namespaceURI:'", "INVALID_CHARACTER_ERR"],
+  ["http://example.com/", "namespaceURI:!", "INVALID_CHARACTER_ERR"],
+  ["http://example.com/", "namespaceURI:@", "INVALID_CHARACTER_ERR"],
+  ["http://example.com/", "namespaceURI:#", "INVALID_CHARACTER_ERR"],
+  ["http://example.com/", "namespaceURI:$", "INVALID_CHARACTER_ERR"],
+  ["http://example.com/", "namespaceURI:%", "INVALID_CHARACTER_ERR"],
+  ["http://example.com/", "namespaceURI:^", "INVALID_CHARACTER_ERR"],
+  ["http://example.com/", "namespaceURI:&", "INVALID_CHARACTER_ERR"],
+  ["http://example.com/", "namespaceURI:*", "INVALID_CHARACTER_ERR"],
+  ["http://example.com/", "namespaceURI:(", "INVALID_CHARACTER_ERR"],
+  ["http://example.com/", "namespaceURI:)", "INVALID_CHARACTER_ERR"],
+  ["http://example.com/", "namespaceURI:+", "INVALID_CHARACTER_ERR"],
+  ["http://example.com/", "namespaceURI:=", "INVALID_CHARACTER_ERR"],
+  ["http://example.com/", "namespaceURI:[", "INVALID_CHARACTER_ERR"],
+  ["http://example.com/", "namespaceURI:]", "INVALID_CHARACTER_ERR"],
+  ["http://example.com/", "namespaceURI:\\", "INVALID_CHARACTER_ERR"],
+  ["http://example.com/", "namespaceURI:/", "INVALID_CHARACTER_ERR"],
+  ["http://example.com/", "namespaceURI:;", "INVALID_CHARACTER_ERR"],
+  ["http://example.com/", "namespaceURI:`", "INVALID_CHARACTER_ERR"],
+  ["http://example.com/", "namespaceURI:<", "INVALID_CHARACTER_ERR"],
+  ["http://example.com/", "namespaceURI:>", "INVALID_CHARACTER_ERR"],
+  ["http://example.com/", "namespaceURI:,", "INVALID_CHARACTER_ERR"],
+  ["http://example.com/", "namespaceURI:a ", "INVALID_CHARACTER_ERR"],
+  ["http://example.com/", "namespaceURI:\"", "INVALID_CHARACTER_ERR"],
+  ["/", "foo", null],
+  ["/", "1foo", "INVALID_CHARACTER_ERR"],
+  ["/", "f1oo", null],
+  ["/", "foo1", null],
+  ["/", ":foo", "INVALID_CHARACTER_ERR"],
+  ["/", "f:oo", null],
+  ["/", "foo:", "INVALID_CHARACTER_ERR"],
+  ["/", "xml", null],
+  ["/", "xmlns", "NAMESPACE_ERR"],
+  ["/", "xmlfoo", null],
+  ["/", "xml:foo", "NAMESPACE_ERR"],
+  ["/", "xmlns:foo", "NAMESPACE_ERR"],
+  ["/", "xmlfoo:bar", null],
+  ["http://www.w3.org/XML/1998/namespace", "foo", null],
+  ["http://www.w3.org/XML/1998/namespace", "1foo", "INVALID_CHARACTER_ERR"],
+  ["http://www.w3.org/XML/1998/namespace", "f1oo", null],
+  ["http://www.w3.org/XML/1998/namespace", "foo1", null],
+  ["http://www.w3.org/XML/1998/namespace", ":foo", "INVALID_CHARACTER_ERR"],
+  ["http://www.w3.org/XML/1998/namespace", "f:oo", null],
+  ["http://www.w3.org/XML/1998/namespace", "foo:", "INVALID_CHARACTER_ERR"],
+  ["http://www.w3.org/XML/1998/namespace", "xml", null],
+  ["http://www.w3.org/XML/1998/namespace", "xmlns", "NAMESPACE_ERR"],
+  ["http://www.w3.org/XML/1998/namespace", "xmlfoo", null],
+  ["http://www.w3.org/XML/1998/namespace", "xml:foo", null],
+  ["http://www.w3.org/XML/1998/namespace", "xmlns:foo", "NAMESPACE_ERR"],
+  ["http://www.w3.org/XML/1998/namespace", "xmlfoo:bar", null],
+  ["http://www.w3.org/XML/1998/namespaces", "xml:foo", "NAMESPACE_ERR"],
+  ["http://www.w3.org/xml/1998/namespace", "xml:foo", "NAMESPACE_ERR"],
+  ["http://www.w3.org/2000/xmlns/", "foo", "NAMESPACE_ERR"],
+  ["http://www.w3.org/2000/xmlns/", "1foo", "INVALID_CHARACTER_ERR"],
+  ["http://www.w3.org/2000/xmlns/", "f1oo", "NAMESPACE_ERR"],
+  ["http://www.w3.org/2000/xmlns/", "foo1", "NAMESPACE_ERR"],
+  ["http://www.w3.org/2000/xmlns/", ":foo", "INVALID_CHARACTER_ERR"],
+  ["http://www.w3.org/2000/xmlns/", "f:oo", "NAMESPACE_ERR"],
+  ["http://www.w3.org/2000/xmlns/", "foo:", "INVALID_CHARACTER_ERR"],
+  ["http://www.w3.org/2000/xmlns/", "xml", "NAMESPACE_ERR"],
+  ["http://www.w3.org/2000/xmlns/", "xmlns", null],
+  ["http://www.w3.org/2000/xmlns/", "xmlfoo", "NAMESPACE_ERR"],
+  ["http://www.w3.org/2000/xmlns/", "xml:foo", "NAMESPACE_ERR"],
+  ["http://www.w3.org/2000/xmlns/", "xmlns:foo", null],
+  ["http://www.w3.org/2000/xmlns/", "xmlfoo:bar", "NAMESPACE_ERR"],
+  ["http://www.w3.org/2000/xmlns/", "foo:xmlns", "NAMESPACE_ERR"],
+  ["foo:", "foo", null],
+  ["foo:", "1foo", "INVALID_CHARACTER_ERR"],
+  ["foo:", "f1oo", null],
+  ["foo:", "foo1", null],
+  ["foo:", ":foo", "INVALID_CHARACTER_ERR"],
+  ["foo:", "f:oo", null],
+  ["foo:", "foo:", "INVALID_CHARACTER_ERR"],
+  ["foo:", "xml", null],
+  ["foo:", "xmlns", "NAMESPACE_ERR"],
+  ["foo:", "xmlfoo", null],
+  ["foo:", "xml:foo", "NAMESPACE_ERR"],
+  ["foo:", "xmlns:foo", "NAMESPACE_ERR"],
+  ["foo:", "xmlfoo:bar", null],
+]
