<html>
  <head>
    <title>AmbientLight Generic Sensor test</title>
    <script type="text/javascript">
      var timeOrigin;
      function onAmbientLightReadingChange(event) {
        if (event.reading.illuminance == 50 &&
            event.reading.timeStamp > timeOrigin &&
            event.reading.timeStamp < window.performance.now()) {
          pass();
        } else {
          fail();
        }
      }

      function start() {
        var sensor = new AmbientLightSensor();
        timeOrigin = window.performance.now();
        sensor.onchange = function(e) {
            onAmbientLightReadingChange(e);
          };
        sensor.start();
      }

      function pass() {
        document.getElementById('status').innerHTML = 'PASS';
        document.location = '#pass';
      }

      function fail() {
        document.location = '#fail';
      }
    </script>
  </head>
  <body onLoad="start()">
    <div id="status">FAIL</div>
  </body>
</html>