function toggleLayer(whichLayer) {
  if (document.getElementById) { 
    var style2 = document.getElementById(whichLayer).style; 
    style2.display = style2.display? "":"block";		
	} 
  else if (document.all) { 
    var style2 = document.all[whichLayer].style; 
    style2.display = style2.display? "":"block";
	} 
  else if (document.layers) { 
    var style2 = document.layers[whichLayer].style; 
    style2.display = style2.display? "":"block";
	}
}