static/js/order.js

@@ -21,6 +21,9 @@ document.addEventListener("DOMContentLoaded", () => {
         setTimeout(() => {
 
             let number_of_drinks = parseFloat(order_number_of_drinks_input.value);
+            if (isNaN(number_of_drinks)) {
+                number_of_drinks = 1;
+            }
             let calculated_sum = order_price_per_drink * number_of_drinks;
             order_sum_element.innerText = new Intl.NumberFormat(undefined, {minimumFractionDigits: 2}).format(calculated_sum);
 
@@ -41,6 +44,10 @@ document.addEventListener("DOMContentLoaded", () => {
 
         event.preventDefault(); // Don't do the default submit action!
 
+        if (isNaN(parseFloat(order_number_of_drinks_input.value))) {
+            order_number_of_drinks_input.value = 1;
+        }
+
         let xhr = new XMLHttpRequest();
         let formData = new FormData(order_form);