How do I create a formula in HTML to reside on my website? For example, I want the user to select a quantity from a drop-down box. Once selected, I want that number to be multiplied by a cost per unit amount, invisible to the user. The total amount should appear on the site.
Ex. I want to order 5 hats, so I choose '5' from a drop-down box. Each hat is $10. Therefore, Total Cost = $50.00.