I don't think thats possible? I can't think how it would be done.
Unless you could find the geographical location, via the ip address.
It might be best to just make it a required field and have your members manually enter the zip code.
When registering on most forums you have to enter your email address and password twice [to make sure you've entered the correct information]
Maybe you could employ this same idea, and have your members enter thier zip code twice to ensure it's correct.
|