testing/web-platform/tests/css/css-anchor-position/reference/anchor-scroll-chained-002-ref.html

<!DOCTYPE html>
<style>
body {
  margin: 0;
}

div {
  width: 100px;
  height: 100px;
}

#scroller1 {
  width: 200px;
  height: 200px;
}

#scroller1,#scroller2 {
  overflow: scroll;
}

#anchor {
  height: 20px;
  background: orange;
}

#anchored1 {
  position: absolute;
  top: 70px;
  background: green;
}

#anchored2 {
  position: absolute;
  top: 170px;
  background: lime;
}

</style>

<div id="scroller1">
  <div style="height: 100px"></div>
  <div id="scroller2">
    <div style="height: 230px"></div>
    <div id="anchor"></div>
    <div style="height: 230px"></div>
  </div>
  <div style="height: 250px"></div>
</div>
<div id="anchored1"></div>
<div id="anchored2"></div>

<script>
scroller1.scrollTop = 80;
scroller2.scrollTop = 200;
</script>