本方法主要用于国内身份证号码的验证，支持15位与最新的18位身份证号码。
<?phpfunction is_idcard( $id ){$id = strtoupper($id);$regx = "/(^\d{15}$)|(^\d{17}([0-9]|X)$)/";$arr_split = array();if(!preg_match($regx, $id)){return FALSE;}//检查15位if(15==strlen($id)){$regx = "/^(\d{6})+(\d{2})+(\d{2})+(\d{2})+(\d{3})$/";@preg_match($regx, $id, $arr_split);//检查生日日期是否正确$dtm_birth = "19".$arr_split[2] . '/' . $arr_split[3]. '/' .$arr_split[4];if(!strtotime($dtm_birth)){return FALSE;} else {return TRUE;}}else{//检查18位$regx = "/^(\d{6})+(\d{4})+(\d{2})+(\d{2})+(\d{3})([0-9]|X)$/";@preg_match($regx, $id, $arr_split);$dtm_birth = $arr_split[2] . '/' . $arr_split[3]. '/' .$arr_split[4];//检查生日日期是否正确if(!strtotime($dtm_birth)){return FALSE;}else{//检验18位身份证的校验码是否正确。//校验位按照ISO 7064:1983.MOD 11-2的规定生成，X可以认为是数字10。$arr_int = array(7, 9, 10, 5, 8, 4, 2, 1, 6, 3, 7, 9, 10, 5, 8, 4, 2);$arr_ch = array('1', '0', 'X', '9', '8', '7', '6', '5', '4', '3', '2');$sign = 0;for ( $i = 0; $i < 17; $i++ ){$b = (int) $id{$i};$w = $arr_int[$i];$sign += $b * $w;}$n = $sign % 11;$val_num = $arr_ch[$n];if ($val_num != substr($id,17, 1)){return FALSE;}else{return TRUE;}}}}
