Update templates/cart.html

templates/cart.html

@@ -413,7 +413,7 @@
             let selectedCoupon = couponDropdown.value.trim(); // Get selected coupon from the dropdown
     
             // If no coupon is selected, alert the user
-            if (!selectedCoupon || selectedCoupon === "None") {
+            if (selectedCoupon === "None" || selectedCoupon === "Null") {
                 alert("Please select a valid coupon before proceeding.");
                 return;
             }