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"; } }