image-not-added.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/image-not-added.html - WPT Dashboard Interop Dashboard

<!DOCTYPE HTML>

<meta charset=utf-8>

<title>Element Timing: do not observe a disconnected image</title>

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

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

<script>

  async_test(function (t) {

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

    const observer = new PerformanceObserver(

      t.step_func_done(() => {

        // The image should not have caused an entry, so fail test.

        assert_unreached('Should not have received an entry!');

})

);

    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.

      const img = document.createElement('img');

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

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

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

      // Image has been created but not added.

      // Wait for 500ms and end test, ensuring no entry was created.

      t.step_timeout(() => {

        t.done();

      }, 500);

};

  }, 'Image which is not added to DOM tree is not observable.');

</script>