third_party/web_platform_tests/dom/nodes/getElementsByClassName-31.htm

<!DOCTYPE html>
<html class=foo>
<meta charset=utf-8>
<title>getElementsByClassName across documents</title>
<link rel=help href="https://dom.spec.whatwg.org/#dom-document-getelementsbyclassname">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<div id=log></div>
<script class=foo>
async_test(function() {
  var iframe = document.createElement("iframe");
  iframe.onload = this.step_func_done(function() {
    var collection = iframe.contentDocument.getElementsByClassName("foo");
    assert_equals(collection.length, 3);
    assert_equals(collection[0].localName, "html");
    assert_equals(collection[1].localName, "head");
    assert_equals(collection[2].localName, "body");
  });
  iframe.src = "getElementsByClassNameFrame.htm";
  document.body.appendChild(iframe);
});
</script>