Add-cart.php Num [ TESTED • CHECKLIST ]

<form method="post" action="add-cart.php"> <input type="hidden" name="product_id" value="123"> <label>Quantity:</label> <input type="number" name="num" value="1" min="1" max="99"> <button type="submit">Add to Cart</button> </form>

Before processing any add-cart request, enforce: add-cart.php num

<?php session_start(); require 'db.php'; // assume DB connection and helper functions &lt;form method="post" action="add-cart

He refreshed the database. The inventory for Item 9021 hadn't decreased. It had increased. form method="post" action="add-cart.php"&gt

add-cart.php?id=100&num=-999

Instead, use a clear, explicit design:

// Fetch product from DB and check stock // ...