var nc = (document.layers)? true:false
var ie = (document.all)? true:false
var n6 = (document.getElementById)? true:false


function muestracapa(id)
{
//  ocultacapa();
  if(ie) {
     document.all[id].style.visibility="visible";
    document.all["grafico"].style.visibility="hidden";
  } else if(nc) {
     document.principal.document.fondo.document.layers[id].visibility="show";
     document.principal.document.fondo.document.layers["grafico"].visibility="hide";
  } else if(n6) {
     document.getElementById(id).style.visibility="visible";
	document.getElementById("grafico").style.visibility="hidden";
 }
}

function ocultacapa(id)
{
   if(ie){
	document.all[id].style.visibility="hidden";
	document.all["grafico"].style.visibility="visible";
           }
   else if(nc){
	document.principal.document.fondo.document.layers[id].visibility="hide";
	document.principal.document.fondo.document.layers["grafico"].visibility="show";
           }
   else if(n6){
	document.getElementById(id).style.visibility="hidden";
	document.getElementById("grafico").style.visibility="visible";
           }
}