function handleForm() {
   if (!isEmpty(document.search.zipcode.value) && !(validZIPCode(document.search.zipcode.value) || validPostalCode(document.search.zipcode.value))) {
      alert ("The Postal Code '" + document.search.zipcode.value + "' is invalid.\n\nPlease specify a Postal Code in either US or Canadian format.");
      document.search.zipcode.select();
      return false;
   }
   if (!isEmpty(document.search.animal_id.value) && !isInteger(document.search.animal_id.value)) {
      alert ("The Dog Id field must be a numeric value.");
      document.search.animal_id.select();
      return false;
   }

   return true;
}