function setAnniv(which){ //which is the index position of the festival in the months array
  var fest = getFestival(which);
  var anniv = fest.anniv;
  var spans = document.getElementsByTagName("span");
  var len = spans.length;
  for (var i=0; i<len; i++){
    if (spans[i].className=="anniv"){
      spans[i].innerHTML = anniv;
    }
  }
}