iv style="width: 40px; height: 20px; overflow: hidden;"></div>
  <div style="width: 20px; height: 10px; display: inline-block;"></div>
  <div style="width: 50px; height: 50px; float: left; shape-outside: inset(20px 0 0 0);"></div>
  <div id="target" style="height: 50px; margin: 10px 0;"></div>
  <div style="width: 20px; height: 10px; display: inline-block;"></div>
</div>
<script>
document.body.offsetTop;
document.getElementById('target').style.height = '10px';
document.body.offsetTop;
</script>
