var selected = {};
function amRegisterClick(map_id, object_id, title, value){
  if (selected[object_id] != undefined && selected[object_id]) {
    // unselect (set it to blue)
    document.getElementById("ammap").setColor(object_id, "#0000ff");
    selected[object_id] = false;
  }
  else {
    // select (set it to red)
    document.getElementById("ammap").setColor(object_id, "#ff0000");
    selected[object_id] = true;
  }
}