intersection-observer/root-margin-in-same-origin-iframe.html

<!DOCTYPE html>

<title>Intersection Observer: root margin is applied when observer is in a same-origin iframe</title>
<link rel="author" title="Kiet Ho" href="mailto:kiet.ho@apple.com">

<script src="/common/rendering-utils.js"></script>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>

<style>
  #iframe {
    width: 40px;
    height: 40px;
    display: block;
    position: fixed;
    left: 0;
    top: -40px;
    border: 0;
  }
</style>

<iframe id="iframe"></iframe>

<script>
  isIntersecting = null;
  window.addEventListener("message", event => {
    isIntersecting = event.data.isIntersecting;
  });

  function loadFrame() {
    return new Promise(resolve => {
      iframe.addEventListener("load", resolve, { once: true });
      iframe.src = "resources/root-margin-in-same-origin-iframe-subframe.html";
    });
  }

  promise_test(async (t) => {
    await loadFrame();

    await waitForAtLeastOneFrame();
    await waitForAtLeastOneFrame();
    await waitForAtLeastOneFrame();

    assert_true(isIntersecting);
  });
</script>