Update: every code file in my project. Is it maybe something to do with the js code for cart section that needs to be refrenced? Because cart is empty when you open the index.php file and through js it is stored in shop section (add to cart button)

index.php

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Hey everyone, I'm working on a small webshop project. I have register and login form which are working fine and are storing data into table users. Now, I have another table: orders, in which I want to transfer data from logged user when he makes order.

users data: id, username, email, password, address, city, country

orders data: id, username, email, address, city, country, item, quantity, price, total_price (where i...