function div_show (id) {
  document.getElementById(id).style.display = 'block';
  document.getElementById('s'+id).innerHTML = '<a href="javascript:div_hide(\''+id+'\')"><img class="on" src="images/off.gif" alt="" border="0" /></a>';
}
function div_hide (id) {
  document.getElementById(id).style.display = 'none';
  document.getElementById('s'+id).innerHTML = '<a href="javascript:div_show(\''+id+'\')"><img class="on" src="images/on.gif" alt="" border="0" /></a>';
}