Credit Card Validation Script

This script checks credit card numbers and expiration dates for validity. You should note that only the format of the expiration date is checked with this script-it doesn't check whether or not the card has actually expired. This script is free to use as long as you don't change any of the comments in the JavaScript source file. If you do not enter a credit card number or expiration date that is formatted correctly it will prompt a popup dialog box that says the credit card has an incorrect number of digits, or includes characters other than numbers that are not allowed. While this script doesn't actually check if a credit card is completely valid or not, it does help limit some of the common mistakes that customers might enter into your forms.