<!DOCTYPE html>
<link rel="help" href="https://drafts.csswg.org/css-contain/#contain-property">
<link rel="help" href="https://crbug.com/1214198">
<link rel="author" title="Koji Ishii" href="mailto:kojii@chromium.org">
<style>
.contain {
  contain: strict;
  display: block;
  width: 100px;
  height: 100px;
}
</style>
<body>
  <div id="outer" class="contain">
    <div>
      <div id="inner" class="contain"></div>
    </div>
  </div>
<script>
  document.body.offsetTop;
  inner.appendChild(document.createTextNode('inner-child'));
  outer.appendChild(document.createTextNode('outer-child'));
</script>
</body>
