<div style='width: 100px; height: 100px; overflow-x: hidden; overflow-y: hidden;'>
  <div id='contenido' style='width: 300px; height: 300px; margin: 0px 0px 0px 0px;'>
    A
 B
 C
 D
 E
 F
 G
 H
 
  </div>
</div>
<input value='^' type='button' 
  onclick="getElementById('contenido').style.marginTop = (parseInt(getElementById('contenido').style.marginTop) - 10) + 'px';">
<input value='v' type='button' 
  onclick="getElementById('contenido').style.marginTop = (parseInt(getElementById('contenido').style.marginTop) + 10) + 'px';">