disconnect-image.html

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This test has a WPT meta file that expects 1 subtest issues.
This WPT test may be referenced by the following Test IDs:
- /element-timing/disconnect-image.html - WPT Dashboard Interop Dashboard

<!DOCTYPE HTML>

<meta charset=utf-8>

<title>Element Timing: element attribute returns null when element is disconnected</title>

<body>

<script src="/resources/testharness.js"></script>

<script src="/resources/testharnessreport.js"></script>

<script src="resources/element-timing-helpers.js"></script>

<script>

  let beforeRender;

  let img;

  async_test(function (t) {

    assert_implements(window.PerformanceElementTiming, "PerformanceElementTiming is not implemented");

    const observer = new PerformanceObserver(

      t.step_func_done(function(entryList) {

        assert_equals(entryList.getEntries().length, 1);

        const entry = entryList.getEntries()[0];

        const pathname = window.location.origin + '/element-timing/resources/square100.png';

        // This method will check that entry.element is |img|.

        checkElement(entry, pathname, 'my_image', 'my_id', beforeRender, img);

        img.parentNode.removeChild(img);

        // After removing image, entry.element should return null.

        assert_equals(entry.element, null);

})

);

    observer.observe({entryTypes: ['element']});

    // We add the image during onload to be sure that the observer is registered

    // in time for it to observe the element timing.

    window.onload = () => {

      // Add image of width equal to 100 and height equal to 100.

      img = document.createElement('img');

      img.src = 'resources/square100.png';

      img.setAttribute('elementtiming', 'my_image');

      img.setAttribute('id', 'my_id');

      document.body.appendChild(img);

      beforeRender = performance.now();

};

  }, 'Disconnected elements have null as their |element| attribute.');

</script>

</body>