<?php 
$IDCard = new IDCard(); 
var_dump($IDCard::isCard($_GET['card'])); 

/** 
 * 身份證處理類 
 */
class IDCard { 

    //檢證身份證是否正確 
    public static function isCard($card) { 
        $card = self::to18Card($card); 
        if (strlen($card) != 18) { 
            return false; 
        } 

        $cardBase = substr($card, 0, 17); 

        return (self::getVerifyNum($cardBase) == strtoupper(substr($card, 17, 1))); 
    } 

  
    //格式化15位身份證號碼為18位 
    public static function to18Card($card) { 
        $card = trim($card); 

        if (strlen($card) == 18) { 
            return $card; 
        } 

        if (strlen($card) != 15) { 
            return false; 
        } 

        // 如果身份證順序碼是996 997 998 999，這些是為百歲以上老人的特殊編碼 
        if (array_search(substr($card, 12, 3), array('996', '997', '998', '999')) !== false) { 
            $card = substr($card, 0, 6) . '18' . substr($card, 6, 9); 
        } else { 
            $card = substr($card, 0, 6) . '19' . substr($card, 6, 9); 
        } 
        $card = $card . self::getVerifyNum($card); 
        return $card; 
    } 

    // 計算身份證校驗碼，根據國家標準gb 11643-1999 
    private static function getVerifyNum($cardBase) { 
        if (strlen($cardBase) != 17) { 
            return false; 
        } 
        // 加權因子 
        $factor = array(7, 9, 10, 5, 8, 4, 2, 1, 6, 3, 7, 9, 10, 5, 8, 4, 2); 

        // 校驗碼對應值 
        $verify_number_list = array('1', '0', 'X', '9', '8', '7', '6', '5', '4', '3', '2'); 

        $checksum = 0; 
        for ($i = 0; $i < strlen($cardBase); $i++) { 
            $checksum += substr($cardBase, $i, 1) * $factor[$i]; 
        } 

        $mod = $checksum % 11; 
        $verify_number = $verify_number_list[$mod]; 

        return $verify_number; 
    } 
}