function switch(div) {
obj=document.getElementById(div);
anc=document.getElementById("a"+div)
switch(obj.style.display)
{
case "none":
  obj.style.display= "block";
  anc.style.display= "none";
  break;    
default:
  obj.style.display= "none";
  anc.style.display= "block";
}
}