gecko-dev/dom/media/test/test_progress.html

<!DOCTYPE HTML>
<html>
<head>
  <title>Media test: progress events</title>
  <script type="text/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
  <script type="text/javascript" src="manifest.js"></script>
</head>
<body>
<pre id="test">
<script class="testbody" type="text/javascript">

var manager = new MediaTestManager;

function do_progress(e) {
  var v = e.target;
  ok(!v._finished, "Check no progress events after completed for " + v._name);
}

function do_ended(e) {
  var v = e.target;
  ok(!v._finished, "Only one ended event for " + v._name);
  v._finished = true;
  v.removeEventListener("ended", do_ended, false);
  v.removeEventListener("progress", do_progress, false);
  removeNodeAndSource(v);
  manager.finished(v.token);
}

function startTest(test, token) {
  var type = /^video/.test(test.type) ? "video" : "audio";
  var v = document.createElement(type);
  v.token = token;
  manager.started(token);
  v.src = test.name;
  v.autoplay = true;
  v._name = test.name;
  v._finished = false;
  v.addEventListener("ended", do_ended, false);
  v.addEventListener("progress", do_progress, false);
  document.body.appendChild(v);
}

SimpleTest.waitForExplicitFinish();
SpecialPowers.pushPrefEnv({"set": [["media.cache_size", 40000]]}, beginTest);
function beginTest() {
  manager.runTests(gProgressTests, startTest);
}
</script>
</pre>
</body>
</html>