function setOptions(chosen) {
var selbox = document.myform.opttwo;
 
selbox.options.length = 0;
if (chosen == "0") {
  selbox.options[selbox.options.length] = new Option('Subcategory','0');
 
}
if (chosen == 10) {
  selbox.options[selbox.options.length] = new Option('Enter number of cast members -->','0');
}
else {
  selbox.options[selbox.options.length] = new Option('Enter keywords -->','0');
}
}