function showLayer(object)
  {
   for (var i=1;i<=10;i++) {
    if (document.getElementById("l"+i)) document.getElementById("l"+i).style.visibility = 'hidden';
   }
   
   if (document.getElementById(object)){
    document.getElementById(object).style.visibility = 'visible';
    document.getElementById(object).style.zorder = 100;
   } 

    return;
  }

function hideLayer() {
   for (var i=1;i<=10;i++) {
    if (document.getElementById("l"+i)) document.getElementById("l"+i).style.visibility = 'hidden';
   }
}