İlk irade geçerli posta kodunun altında fonksiyon, eğer geçerli değil, false döndürür. geçerli, eğer outcode ve InCode arasındaki boşluk bir posta kodu dönecektir olursa olsun, bunu alan veya bir posta kodu verir.
function checkPostcode (&$toCheck) {
// Permitted letters depend upon their position in the postcode.
$alpha1 = "[abcdefghijklmnoprstuwyz]"; // Character 1
$alpha2 = "[abcdefghklmnopqrstuvwxy]"; // Character 2
$alpha3 = "[abcdefghjkpmnrstuvwxy]"; // Character 3
$alpha4 = "[abehmnprvwxy]"; // Character 4
$alpha5 = "[abdefghjlnpqrstuwxyz]"; // Character 5
// Expression for postcodes: AN NAA, ANN NAA, AAN NAA, and AANN NAA with a space
$pcexp[0] = '^('.$alpha1.'{1}'.$alpha2.'{0,1}[0-9]{1,2})([[:space:]]{0,})([0-9]{1}'.$alpha5.'{2})$';
// Expression for postcodes: ANA NAA
$pcexp[1] = '^('.$alpha1.'{1}[0-9]{1}'.$alpha3.'{1})([[:space:]]{0,})([0-9]{1}'.$alpha5.'{2})$';
// Expression for postcodes: AANA NAA
$pcexp[2] = '^('.$alpha1.'{1}'.$alpha2.'{1}[0-9]{1}'.$alpha4.')([[:space:]]{0,})([0-9]{1}'.$alpha5.'{2})$';
// Exception for the special postcode GIR 0AA
$pcexp[3] = '^(gir)(0aa)$';
// Standard BFPO numbers
$pcexp[4] = '^(bfpo)([0-9]{1,4})$';
// c/o BFPO numbers
$pcexp[5] = '^(bfpo)(c\/o[0-9]{1,3})$';
// Overseas Territories
$pcexp[6] = '^([a-z]{4})(1zz)$/i';
// Load up the string to check, converting into lowercase
$postcode = strtolower($toCheck);
// Assume we are not going to find a valid postcode
$valid = false;
// Check the string against the six types of postcodes
foreach ($pcexp as $regexp) {
if (ereg($regexp,$postcode, $matches)) {
// Load new postcode back into the form element
$postcode = strtoupper ($matches[1] . ' ' . $matches [3]);
// Take account of the special BFPO c/o format
$postcode = ereg_replace ('C\/O', 'c/o ', $postcode);
// Remember that we have found that the code is valid and break from loop
$valid = true;
break;
}
}
// Return with the reformatted valid postcode in uppercase if the postcode was
// valid
if ($valid){
$toCheck = $postcode;
return true;
}
else return false;
}