I have a web site and I wish to include two PayPal Add to Cart buttons. One is a purchased product and the other is an Add to Cart button that lets the user decide on an amount to donate. I would like to have the Shopping Cart display the total of both items so that there is only one PayPal or credit card transaction. PayPal has a Donate button but that would require a separate transaction rather than one for both items.

I have some javascript that prompts the user to enter the amount in a variable labeled "donation" and I have verified this code works. But the PayPal HTML button code appears to require a specific amount. For example, one line of code is: input type "hidden" name = "amount" value= "5.25". I would like to substitute the "donation" variable for the 5.25. After talking with PayPal I get the impression this can't be done but I thought I would see if someone with PayPal, HTML, and JavaScript might have an idea or suggestion.