css/cssom-view/visual-scrollIntoView-003.html

<!DOCTYPE html>
<html>
<meta name="viewport" content="width=device-width,initial-scale=1">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="/resources/testdriver.js"></script>
<script src="/resources/testdriver-actions.js"></script>
<script src="/resources/testdriver-vendor.js"></script>
<script src="support/action-utils.js"></script>
<link rel="help" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1951021">
<link rel="help" href="https://drafts.csswg.org/cssom-view/#perform-a-scroll">
<style>
body {
  margin: 0px;
  padding: 0px;
}
#container {
  position: fixed;
  width: 100%;
  height: 100%;
  top: 0px;
  left: 0px;
}
#banner {
  position: fixed;
  bottom: 0px;
  left: 0px;
  right: 0px;
  background-color: blue;
}
</style>
<div id="anchor"></div>
<div id="container">
  <aside id="banner"></aside>
</div>
<script>
promise_test(async t => {
  assert_equals(window.scrollY, 0);
  assert_equals(visualViewport.scale, 1.0);
  assert_equals(visualViewport.pageTop, 0);

  // Pinch zoom in this document.
  await pinch_zoom_action();

  assert_greater_than(visualViewport.scale, 1.0);

  // Suppose that the pinch zoom-in gesture at the center of the document did
  // move the visual viewport offset.
  assert_greater_than(visualViewport.pageTop, 0);

  // Move to zero offset of the visual viewport.
  let scrollPromise =
      new Promise(resolve => visualViewport.addEventListener("scroll", resolve));
  document.querySelector('#anchor').scrollIntoView({ behavior: "instant" });
  await scrollPromise;

  assert_equals(visualViewport.pageTop, 0);

  // Now trigger a scrollIntoView call to an element inside nested position:fixed elements.
  scrollPromise =
      new Promise(resolve => visualViewport.addEventListener("scroll", resolve));
  document.querySelector("#banner").scrollIntoView({ behavior: "instant" });
  await scrollPromise;

  assert_greater_than(visualViewport.pageTop, 0);
}, "Element.scrollIntoView scrolls visually to an element in nested position: fixed elements");
</script>