Event.observe(window, 'load', initOrder, false);

function initOrder() {

  function toggleFormHandler(event) {
    var elem = event.element();
    toggleForm(elem);
  }

  function toggleForm(order) {
    if (order.value == 0) {
      Element.hide('tour-rez');
      Element.show('golf-rez');
    }
    else {
      Element.hide('golf-rez');
      Element.show('tour-rez');
    }
  }

  // display form depending on currently checked radio
  var order = $$('input[type="radio"][name="order"]').find(function(re) {return re.checked;});
  toggleForm(order);

  // onclick functions for each radio element
  $$('input[type="radio"][name="order"]')[0].observe('click', toggleFormHandler);
  $$('input[type="radio"][name="order"]')[1].observe('click', toggleFormHandler);

}