function toggleLayer(whichLayer,whichLayera){
	if (document.getElementById){
		var estilo = document.getElementById(whichLayer).style; estilo.display = estilo.display? "":"block";
		var estilo2 = document.getElementById(whichLayera).style; estilo2.display = estilo2.display? "":"none";
	}
	else if (document.all){
		// this is the way old msie versions work
		var estilo = document.all[whichLayer].style; estilo.display = estilo.display? "":"block";
		var estilo2 = document.all[whichLayera].style; estilo2.display = estilo2.display? "":"none";
	}
	else if (document.layers){
		// this is the way nn4 works
		var estilo = document.layers[whichLayer].style; estilo.display = estilo.display? "":"block";
		var estilo2 = document.layers[whichLayera].style; estilo2.display = estilo2.display? "":"none";
	}
}