I didn't see it listed so far, but checkout forms that require you to select the type of credit card you have. Since the card (Mastercard, Visa, Discover, AMEX)

I didn't see it listed so far, but checkout forms that require you to select the type of credit card you have. Since the card (Mastercard, Visa, Discover, AMEX) can be determined by the first digit. I don't see too many sites that require something like this anymore, but every now and then one pops up.