// needs to have an input element to reference 
//<input id="map"   name="map"  class='mapdisplay'  type="image" src="asdf" onClick="map_checkMap(this.value,'')" />
function getMap(){
  var map;
  try{
    map = document.getElementById('map');
  } catch(err){alert('getMap(): map is not available');}

  return map;
}