function setOptions(chosen) {
var selbox = document.product_details.opttwo;

selbox.options.length = 0;
if (chosen == " ") {
  selbox.options[selbox.options.length] = new Option('Select one of the options above',' ');

}
if (chosen == "1") {
  selbox.options[selbox.options.length] = new Option('Select a sub-category','#');
  selbox.options[selbox.options.length] = new Option('Mechanical Winding Machine','#');
  selbox.options[selbox.options.length] = new Option('Semi Automatic CNC Winding Machine','#');
  selbox.options[selbox.options.length] = new Option('Fully Automatic Winding Machine','#');
  selbox.options[selbox.options.length] = new Option('Armature Winding Machine','AWM');
}
if (chosen == "2") {
  selbox.options[selbox.options.length] = new Option('Select a sub-category','#');
  selbox.options[selbox.options.length] = new Option('PLA Relays','twoone');
  selbox.options[selbox.options.length] = new Option('PROTEC Relays','twotwo');
  selbox.options[selbox.options.length] = new Option('Krome Relays','twotwo');
  selbox.options[selbox.options.length] = new Option('Counter Meter','twotwo');
  selbox.options[selbox.options.length] = new Option('Raj Micro Switches','twotwo');
  selbox.options[selbox.options.length] = new Option('Raj Toggle Switches','twotwo');
  selbox.options[selbox.options.length] = new Option('Rotary Switches','twotwo');
  selbox.options[selbox.options.length] = new Option('CE Counter Meter','twotwo');
  selbox.options[selbox.options.length] = new Option('Road Measurer Meter','twotwo');
  selbox.options[selbox.options.length] = new Option('Petrol Pump Totaliser','twotwo');
  selbox.options[selbox.options.length] = new Option('Time Totaliser','twotwo');
}
if (chosen == "3") {
  selbox.options[selbox.options.length] = new Option('Select a cub-category','#');
  selbox.options[selbox.options.length] = new Option('Winding Machines','threeone');
  }
}