<!DOCTYPE html>
<div id=one style="width: 100px; height: 100px; writing-mode: horizontal-tb; overflow: scroll;">
  <div style="width: 192px; height: 192px; border: 4px solid black;"></div>
</div>
<div id=two style="width: 100px; height: 100px; writing-mode: vertical-rl; overflow: scroll; margin-top: 1em;">
  <div style="width: 192px; height: 192px; border: 4px solid black;"></div>
</div>
<script>
document.body.offsetTop;
one.style.writingMode = "vertical-rl";
two.style.writingMode = "horizontal-tb";
</script>