1 /** 2  * 验证身份证格式有效性 3  * @param type $id_card 4  * @return boolean 5  */ 6 function validation_filter_id_card($id_card) { 7     if (strlen($id_card) == 18) { 8         return idcard_checksum18($id_card); 9     } elseif ((strlen($id_card) == 15)) {10         $id_card = idcard_15to18($id_card);11         return idcard_checksum18($id_card);12     } else {13         return false;14     }15 }16 17 // 计算身份证校验码，根据国家标准GB 11643-199918 function idcard_verify_number($idcard_base) {19     if (strlen($idcard_base) != 17) {20         return false;21     }22 //加权因子23     $factor = array(7, 9, 10, 5, 8, 4, 2, 1, 6, 3, 7, 9, 10, 5, 8, 4, 2);24 //校验码对应值25     $verify_number_list = array('1', '0', 'X', '9', '8', '7', '6', '5', '4', '3', '2');26     $checksum = 0;27     for ($i = 0; $i < strlen($idcard_base); $i++) {28         $checksum += substr($idcard_base, $i, 1) * $factor[$i];29     }30     $mod = $checksum % 11;31     $verify_number = $verify_number_list[$mod];32     return $verify_number;33 }34 35 // 将15位身份证升级到18位36 function idcard_15to18($idcard) {37     if (strlen($idcard) != 15) {38         return false;39     } else {40 // 如果身份证顺序码是996 997 998 999，这些是为百岁以上老人的特殊编码41         if (array_search(substr($idcard, 12, 3), array('996', '997', '998', '999')) !== false) {42             $idcard = substr($idcard, 0, 6) . '18' . substr($idcard, 6, 9);43         } else {44             $idcard = substr($idcard, 0, 6) . '19' . substr($idcard, 6, 9);45         }46     }47     $idcard = $idcard . idcard_verify_number($idcard);48     return $idcard;49 }50 51 // 18位身份证校验码有效性检查52 function idcard_checksum18($idcard) {53     if (strlen($idcard) != 18) {54         return false;55     }56     $idcard_base = substr($idcard, 0, 17);57     if (idcard_verify_number($idcard_base) != strtoupper(substr($idcard, 17, 1))) {58         return false;59     } else {60         return true;61     }62 }