third_party/web_platform_tests/dom/nodes/Node-lookupPrefix.xhtml

<html xmlns="http://www.w3.org/1999/xhtml" xmlns:x="test">
<head>
<title>Node.lookupPrefix</title>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
</head>
<body xmlns:s="test">
<div id="log"/>
<x xmlns:t="test"><!--comment--><?test test?>TEST<x/></x>
<script>
function lookupPrefix(node, ns, prefix) {
  test(function() {
    assert_equals(node.lookupPrefix(ns), prefix)
  })
}
var x = document.getElementsByTagName("x")[0];
lookupPrefix(document, "test", "x") // XXX add test for when there is no documentElement
lookupPrefix(document, null, null)
lookupPrefix(x, "http://www.w3.org/1999/xhtml", null)
lookupPrefix(x, "something", null)
lookupPrefix(x, null, null)
lookupPrefix(x, "test", "t")
lookupPrefix(x.parentNode, "test", "s")
lookupPrefix(x.firstChild, "test", "t")
lookupPrefix(x.childNodes[1], "test", "t")
lookupPrefix(x.childNodes[2], "test", "t")
lookupPrefix(x.lastChild, "test", "t")
x.parentNode.removeChild(x)
</script>
</body>
</html>