function change(vd) 
   {  
  var ob=document.getElementById(vd);  
  if(ob.style.display=="block")
  {
     ob.style.display="none";
     var ob2=document.getElementById('s'+vd);
  }
  else
  {
    ob.style.display="block";
    var ob2=document.getElementById('s'+vd);
  }
   }