Please help me. The selected product id and quantity will display on the cart area but the inventory will not show the remaining stocks. When I enter the same product id, the amount will be updated but it will show two times in the cart area. How to correct this? I will add a cancel button that when the user clicks, the quantity will revert to its original value.
Lastly, how can I multiply the sales price column and buy part column in the table to get the total price? Thank you.