function switchlayer(Layer_Name)
{
  var GECKO = document.getElementById? 1:0 ;
  var NS = document.layers? 1:0 ;
  var IE = document.all? 1:0 ;

  if (GECKO)
       {document.getElementById(Layer_Name).style.visibility=
	   (document.getElementById(Layer_Name).style.visibility=='visible') ? 'hidden' : 'visible';}
  else if (NS)
       {document.layers[Layer_Name].visibility=(document.layers[Layer_Name].visibility==
	   'visible') ? 'hidden' : 'visible';}
  else if (IE)
       {document.all[Layer_Name].style.visibility=(document.all[Layer_Name].style.visibility==
	   'visible') ? 'hidden' : 'visible';}
}