css/css-scroll-anchoring/focus-prioritized.html

<!DOCTYPE html>
<meta charset="utf8">
<title>CSS Scroll Anchoring: prioritize focused element</title>
<link rel="author" title="Vladimir Levin" href="mailto:vmpstr@chromium.org">
<link rel="help" href="https://drafts.csswg.org/css-scroll-anchoring/#anchor-node-selection">
<meta name="assert" content="anchor selection prioritized focused element">

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

<style>
body { height: 4000px }
.spacer { height: 100px }
#growing { height: 100px }
#focused { height: 10px }
</style>

<div class=spacer></div>
<div class=spacer></div>
<div class=spacer></div>
<div class=spacer></div>
<div id=growing></div>
<div class=spacer></div>
<div id=focused contenteditable></div>
<div class=spacer></div>
<div class=spacer></div>

<script>
async_test((t) => {
  document.scrollingElement.scrollTop = 150;
  focused.focus();

  const target_rect = focused.getBoundingClientRect();
  growing.style.height = "3000px";

  requestAnimationFrame(() => {
    t.step(() => {
      const new_rect = focused.getBoundingClientRect();
      assert_equals(new_rect.x, target_rect.x, "x coordinate");
      assert_equals(new_rect.y, target_rect.y, "y coordinate");
      assert_not_equals(document.scrollingElement.scrollTop, 150, "scroll adjusted");
    });
    t.done();
  });
}, "Anchor selection prioritized focused element.");
</script>