Use zip code ranges for each state to perform a basic STATE/ZIP validation. Designed to go one step beyond checking for a valid state code and a numeric zip code. Catches
additional data entry error without relying on another web site or maintaining a current CITY/STATE/ZIP database. This code currently serves as a pre-edit to a credit card
address verification check. Note: PHP 4 is required to use foreach, but a do-while loop can be substituted to use with PHP 3.