function show( id ){
var sid = id;
document.getElementById('sub1').style.display="none";
document.getElementById('sub2').style.display="none";
document.getElementById('sub3').style.display="none";
document.getElementById('sub4').style.display="none";
document.getElementById('sub5').style.display="none";
document.getElementById('sub6').style.display="none";
document.getElementById('sub7').style.display="none";

var x = document.getElementById( sid );
if(x != null){
x.style.display="block";
}
}