function n2wChange(sel_obj, sel_name) {
  var obj = document.getElementById(sel_name);
  obj.innerHTML = n2w_ranges[sel_obj.value] != '' ? text_range + ': ' + n2w_ranges[sel_obj.value] : '';
  updatePriceInfo();
}
function w2nChange() {
  updatePriceInfo();
}
function calculateUnitsRequired() {
  var obj_src_type = document.getElementById('n2t_input_type');
  var obj_src_data = document.getElementById('n2t_input_data');
  var obj_dst_type = document.getElementById('n2t_output_type');
  var amount       = 0;
  if (obj_src_data.value == '' ||
      isNaN(parseInt(obj_src_data.value.replace(/ /,'')))) {
    amount += (obj_src_type.value == '_auto_') ? langs_count : 1;
  }
  if (obj_dst_type.value != '_number_') amount ++;
  return amount;
}