<!DOCTYPE html>
<html>
  <body onload="loaded()">
    <div style="position: relative; top: 100px; overflow: scroll; width: 100px; height: 100px;">
      <div style="height: 200px"></div></div>
    <script>
      function loaded() {
        var insPoint = document.querySelector("div");
        insPoint.scrollTop = 50;
      }
    </script>
  </body>
</html>