Codebase Browser
chromium
Go to App

chromium/third_party/blink/web_tests/external/wpt/html/semantics/embedded-content/media-elements/track/track-element/track-element-dom-change.html 

<!DOCTYPE html>
<title>Simple DOM mutations with track element</title>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script>
test(function() {
    var video = document.createElement("video");
    var testTrack = document.createElement("track");

    // Append the track element to the video element.
    video.appendChild(testTrack);

    // Set the mode of the text track to "showing".
    testTrack.track.mode = "showing";
});
</script>