map.Event.bind('overlayClick', function(overlay) {
  if (overlay instanceof longdo.Marker) {
    document.getElementById('overlayselect').innerHTML = 'Marker';
  } else if(overlay instanceof longdo.Polyline){
    document.getElementById('overlayselect').innerHTML = 'Polyline';
  } else if(overlay instanceof longdo.Polygon){
    document.getElementById('overlayselect').innerHTML = 'Polygon';
  } else if(overlay instanceof longdo.Dot){
    document.getElementById('overlayselect').innerHTML = 'Dot';
  } else if(overlay instanceof longdo.Circle){
    document.getElementById('overlayselect').innerHTML = 'Circle';
  }
});

• overlayClick: เหตุการณ์ในขณะที่เกิดการคลิก Overlay