function floorMap(selected){
  if (! document.getElementById) return;
  for (i = 1; i <= 4; i++) {
    if (! document.getElementById("floorGuide0" + i)) continue;
    if (i == selected) {
      document.getElementById("floorGuide0" + i).style.visibility = "visible";
    } else {
      document.getElementById("floorGuide0" + i).style.visibility = "hidden";
    }
  }
}