<!DOCTYPE html>
<html>
  <body>
    <span style="display:table">
      <span style="display: table-cell">
        Cell 1
      </span>
      <script type="text/javascript">document.body.offsetWidth</script>
      <span style="display: table-cell">
        Cell 2
      </span>
    </span>
  </body>
</html>