function rollover_image_on(area) {

  mapimage = document.getElementById('yourarea-map');
  switch(area)
  {
  case 1:
    mapimage.src = '/images/maps/rollover_1.gif';
    break    
  case 2:
    mapimage.src = '/images/maps/rollover_2.gif';
    break  
  case 3:
    mapimage.src = '/images/maps/rollover_3.gif';
    break
  case 4:
    mapimage.src = '/images/maps/rollover_4.gif';
    break
  case 5:
    mapimage.src = '/images/maps/rollover_5.gif';
    break
  case 6:
    mapimage.src = '/images/maps/rollover_6.gif';
    break          
  case 7:
    mapimage.src = '/images/maps/rollover_7.gif';
    break
  case 8:
    mapimage.src = '/images/maps/rollover_8.gif';
    break
  case 9:
    mapimage.src = '/images/maps/rollover_9.gif';
    break
  }

}

function rollover_image_off() {
  mapimage = document.getElementById('yourarea-map');
  mapimage.src = '/images/maps/cluster_map.gif';
}