function updateZone(country_id) {
  zone = document.getElementById('zone_id');
   
  zone.options.length = 0;
  
  zone.options[zone.options.length] = new Option(text, '0');

  for (i = 0; i < zones.length; i++) {
	
    if (zones[i][0] == country_id) {	 	
	  zone.options[zone.options.length] = new Option(zones[i][2], zones[i][1]);
	}
	
	if (zones[i][1] == zone_id) {
	  zone.value = zone_id;
	}
  }
  
  if (zone.value == '') {
	zone.value = 0;  
  }  
}