var coup1="VIP2173";
var coup2="vip2173";

function CalculateOrder(form) {

 if (form.text1.value == coup1)
 {
 form.discount_rate.value = "10";
 form.discount_rate2.value = "10";
 form.on20.value = "Coupon";
 form.os20.value = "VIP Member Discount 10%";
 }
  if (form.text1.value == coup2)
 {
 form.discount_rate.value = "10";
 form.discount_rate2.value = "10";
 form.on20.value = "Coupon";
 form.os20.value = "VIP Member Discount 10%";
 }
}