function selectLayer1(div, i)
{
 switch(i)
 {
 case 1:
document.getElementById(div+"1").style.display="block";
document.getElementById(div+"2").style.display="none";
document.getElementById(div+"3").style.display="none";
document.getElementById(div+"4").style.display="none";
 break;
case 2:
document.getElementById(div+"1").style.display="none";
document.getElementById(div+"2").style.display="block";
document.getElementById(div+"3").style.display="none";
document.getElementById(div+"4").style.display="none";
 break;
case 3:
document.getElementById(div+"1").style.display="none";
document.getElementById(div+"2").style.display="none";
document.getElementById(div+"3").style.display="block";
document.getElementById(div+"4").style.display="none";
 break;
 case 4:
document.getElementById(div+"1").style.display="none";
document.getElementById(div+"2").style.display="none";
document.getElementById(div+"3").style.display="none";
document.getElementById(div+"4").style.display="block";
 break;
 }
}