function change(d,pic) {
   var div = document.getElementById("div_" + d);
   var plc = document.getElementById("placeholder" + d);
   plc.src = pic;
   div.style.display='';  
}
function hide(d){
   if (!document.getElementById) return false;
   var div = document.getElementById("div_" + d);
   div.style.display = 'none' ;
}