var coup1="DTOXCORP";

function CalculateOrder(form) {

 if (form.text1.value == coup1)
 {
 form.discount_rate.value = "10";
 form.discount_rate2.value = "10";
 form.on0.value = "Coupon";
 form.os0.value = "Dtox corporate - Discount 10%";
 }  
}