Use Coupon : <input   id="coupoin_code"  name="pks_coupon_code" onkeyup="checkcoupon();""  type="text" minlength="9"  maxlength="9" size="8">
      <br>  <span id="couponmessage" style="font-size:24px;color:red"></span>
                                      <span id="checkCouponError" style="color:red"></span>