Authenticate Zip Field For Free

To validate a zip code: Use the RegExp. test() method to check for a regular expression. The regular expression should check if the value consists of 5 digits or 5 digits followed by a hyphen and 4 digits. If the condition is met, the zip code is valid.

A valid postal code depends on where you live. The specific order of the numbers of a ZIP code are important and can be used to help identify what state an individual lives in and where their mail is sorted. The first three digits of a ZIP code correspond to the central mail processing facility used to sort the mail.

If the zip check has failed, it's because the bank/credit company is telling us that the zip code does not match the one it has on file. If the cardholder has recently moved, it may take their bank a while to have the correct zip code on file for them.

Postal codes that don't exist in the system often represent obscure or otherwise small geographical zones with minimal internet activity. Additionally, certain ZIP or postal codes that are in close proximity to or overlap with other ZIP or postal codes may be considered invalid.

Look Up a ZIP Code? By Address. Enter a corporate or residential street address, city, and state to see a specific ZIP Code?. Find by Address. By City and State. Enter city and state to see all the ZIP Codes? for that city. Find by City & State. Cities by ZIP Code? Enter a ZIP Code? to see the cities it covers.

So what do the extra numbers mean? These last 4 digits represent specific delivery routes within delivery areas. This extra detail means an even more precise matching to a more granular level. It could represent a handful of houses on one side of a street, or even a single building that receives a high volume of mail.

11111 is not a valid 5 digit ZIP Code, but there are valid ZIP Codes that start with 111: 11101, 11102, etc. Once position 28 was changed to Y, then MSP considered 11111 as an Invalid zip, because it looked at all 5 digits.