diff -r 000000000000 -r 6474c204b198 parser/htmlparser/tests/mochitest/parser_web_testrunner.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/parser/htmlparser/tests/mochitest/parser_web_testrunner.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,132 @@
+/* -*- Mode: Java; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+ 
+/**
+ * Runs html5lib-formatted test cases in the browser. Requires SimpleTest.
+ *
+ * Define an array named parserDatFiles before loading this script,
+ * and it will load each of those dat files into an array, then run
+ * the test parser on each and run the tests by assigning the input
+ * data to an iframe's url.
+ *
+ * Your test document should have an element with id "display" and
+ * an iframe with id "testframe".
+ */
+
+var functionsToRunAsync = [];
+
+window.addEventListener("message", function(event) {
+  if (event.source == window && event.data == "async-run") {
+    event.stopPropagation();
+    var fn = functionsToRunAsync.shift();
+    fn();
+  }
+}, true);
+
+function asyncRun(fn) {
+  functionsToRunAsync.push(fn);
+  window.postMessage("async-run", "*");
+}
+
+function writeErrorSummary(input, expected, got, isTodo) {
+  if (isTodo) {
+    $("display").appendChild(createEl('h2', null, "Unexpected Success:"));
+  } else {
+    $("display").appendChild(createEl('h2', null, "Unexpected Failure:"));
+  }
+  $("display").appendChild(createEl('br'));
+  $("display").appendChild(createEl('span', null, "Matched: "));
+  $("display").appendChild(document.createTextNode("" + (expected == got)));
+  var pre = createEl('pre');
+  pre.appendChild(document.createTextNode("Input: \n" + input, "\n-\n"));
+  pre.appendChild(document.createTextNode("Expected:\n" + expected, "\n-\n"));
+  pre.appendChild(document.createTextNode("Output:\n" + got + "\n-\n"));
+  $("display").appendChild(pre);
+  $("display").appendChild(createEl('hr'));
+}
+
+/**
+ * Control will bounce back and forth between nextTest() and the
+ * event handler returned by makeTestChecker() or the callback returned by
+ * makeFragmentTestChecker() until the 'testcases' iterator is spent.
+ */
+function makeTestChecker(input, expected, errors) {
+  return function (e) {
+    var domAsString = docToTestOutput(e.target.contentDocument);
+    if (html5Exceptions[input]) {
+      todo_is(domAsString, expected, "HTML5 expected success.");
+      if (domAsString == expected) {
+        writeErrorSummary(input, expected, domAsString, true);
+      }
+    } else {
+      is(domAsString, expected, "HTML5 expected success.");
+      if (domAsString != expected) {
+        writeErrorSummary(input, expected, domAsString, false);
+      }
+    }
+    nextTest(e.target);
+  } 
+}
+
+function makeFragmentTestChecker(input, 
+                                 expected, 
+                                 errors, 
+                                 fragment, 
+                                 testframe) {
+  return function () {
+    var context = document.createElementNS("http://www.w3.org/1999/xhtml",
+                                           fragment);
+    context.innerHTML = input;
+    var domAsString = fragmentToTestOutput(context);
+    is(domAsString, expected, "HTML5 expected success. " + new Date());
+    if (domAsString != expected) {
+      writeErrorSummary(input, expected, domAsString, false);
+    }
+    nextTest(testframe);
+  } 
+}
+
+var testcases;
+function nextTest(testframe) {
+  var test = 0;
+  try {
+    var [input, output, errors, fragment] = testcases.next();
+    if (fragment) {
+      asyncRun(makeFragmentTestChecker(input, 
+                                       output, 
+                                       errors, 
+                                       fragment, 
+                                       testframe));
+    } else {
+      dataURL = "data:text/html;charset=utf-8," + encodeURIComponent(input);
+      testframe.onload = makeTestChecker(input, output, errors);
+      testframe.src = dataURL;
+    }
+  } catch (err if err instanceof StopIteration) {
+    SimpleTest.finish();
+  }
+}
+
+var testFileContents = [];
+function loadNextTestFile() {
+  var datFile = parserDatFiles.shift();
+  if (datFile) {
+    var xhr = new XMLHttpRequest();
+    xhr.onreadystatechange = function () {
+      if (this.readyState == 4) {
+        testFileContents.push(this.responseText);
+        loadNextTestFile();
+      }
+    };
+    xhr.open("GET", "html5lib_tree_construction/" + datFile);
+    xhr.send();
+  } else {
+    testcases = test_parser(testFileContents);
+    nextTest($("testframe"));
+  }
+}
+
+addLoadEvent(loadNextTestFile);
+SimpleTest.waitForExplicitFinish();