document.querySelector("video");

    var trackElements = document.querySelectorAll("track");
    for (var i = 0; i < video.textTracks.length; i++)
        trackElements[i].onload = t.step_func(trackLoaded);

    enableAllTextTracks(video.textTracks);

    var numberOfTracksLoaded = 0;
    function trackLoaded() {
        numberOfTracksLoaded++;
        if (numberOfTracksLoaded != 2)
            return;

        testTrack0();
        testTrack1();
        t.done();
    }

    function testTrack0() {
       