var coup1="NZ15OFF";

function CalculateOrder(form){
 if (form.coupon.value.toUpperCase() == coup1)
 {
  form.discount_amount.value = "15";
  form.discount_amount2.value = "15";
  form.on0.value = "Coupon";
  form.os0.value = "NZ15OFF - Discount $15";
 }else{
  form.discount_amount.value = "0.0";
  form.discount_amount2.value = "0.0";
  form.on0.value = "";
  form.os0.value = "";
 }
}