php正则判断是否为合法身份证号的方法

/** * 判断是否为合法的身份证号码 * @param $mobile * @return int */function isCreditNo($vStr){  $vCity = array(    '11','12','13','14','15','21','22',    '23','31','32','33','34','35','36',    '37','41','42','43','44','45','46',    '50','51','52','53','54','61','62',    '63','64','65','71','81','82','91'  );  if (!preg_match('/^([/d]{17}[xX/d]|[/d]{15})$/', $vStr)) return false;  if (!in_array(substr($vStr, 0, 2), $vCity)) return false;  $vStr = preg_replace('/[xX]$/i', 'a', $vStr);  $vLength = strlen($vStr);  if ($vLength == 18) {    $vBirthday = substr($vStr, 6, 4) . '-' . substr($vStr, 10, 2) . '-' . substr($vStr, 12, 2);  } else {    $vBirthday = '19' . substr($vStr, 6, 2) . '-' . substr($vStr, 8, 2) . '-' . substr($vStr, 10, 2);  }  if (date('Y-m-d', strtotime($vBirthday)) != $vBirthday) return false;  if ($vLength == 18) {    $vSum = 0;    for ($i = 17 ; $i >= 0 ; $i--) {      $vSubStr = substr($vStr, 17 - $i, 1);      $vSum += (pow(2, $i) % 11) * (($vSubStr == 'a') ? 10 : intval($vSubStr , 11));    }    if($vSum % 11 != 1) return false;  }  return true;}