function updateStar(id_film, nr) {
 for(i = 1; i <= nr; i++) {
  var pool = document.getElementById("star_" + i + "_" + id_film);
  
  if(!pool) continue;
  pool.className = 'ystar';
 }
}
function backStar(id_film) {
 for(i = 0; i <= 6; i++) {
  pool = document.getElementById("star_" + i + "_" + id_film);
  
  if(!pool) continue;
  
  pool.className = 'wstar';
 }
}