Zip Code Formatting

Is there any simple way to structure a field to accept U.S. zip codes whether they are standard 5-digit values, or in USPS "Zip+4" format. In browsers equipped with autofill capailtiies, when the user has populated his/her zipcode with the latter, if the zip field has been limited to 5 numbers (and assuming this field is required), the Submit button won't work until the user deletes the extra character. On the other hand, increasing the field maximum length to 10 characters (to include the hyphen separating the zipcode from the subsequent 4 characters, increases the odds that the user will enter an invalid zip code.