本文实例讲述了php正则判断是否为合法身份证号的方法。分享给大家供大家参考，具体如下：
/**
* 判断是否为合法的身份证号码
* @param $mobile
* @return int
*/
function iscreditno($vstr){
$vcity = array(
'11','12','13','14','15','21','22',
'23','31','32','33','34','35','36',
'37','41','42','43','44','45','46',
'50','51','52','53','54','61','62',
'63','64','65','71','81','82','91'
);
if (!preg_match('/^([d]{17}[xxd]|[d]{15})$/', $vstr)) return false;
if (!in_array(substr($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;
}
