PHP verify ID card collection_PHP tutorial

Personally, I feel that the functions related to ID cards are quite useful. Especially when conducting online questionnaires, it is very useful to verify the ID card in personal information. I would like to post it and share it.

＜?php
// Calculate ID card verification code according to national standard GB 11643-1999
function idcard_verify_number($idcard_base){
　if (strlen($idcard_base) != 17){ return false; }
// Weighting factor
$factor = array(7, 9, 10, 5, 8, 4, 2, 1, 6, 3, 7, 9, 10, 5, 8, 4 , 2);

// Verification code corresponding value
$verify_number_list = array('1', '0', 'X', '9', '8', '7', '6', '5', '4', '3', '2');

$checksum = 0;
for ($i = 0; $i $checksum += substr($idcard_base, $i, 1) * $ factor[$i];
　}

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

return $verify_number;
}

// Upgrade the 15-digit ID card to 18-digits
function idcard_15to18($idcard){
　if (strlen($idcard) != 15){
　return false;
　}else {
// If the ID card sequence code is 996 997 998 999, these are special codes for people over 100 years old
if (array_search(substr($idcard, 12, 3), array('996', '997', '998', '999')) !== false){
　 $idcard = substr($idcard, 0, 6) . '18'. substr($idcard, 6, 9);
　}else{
　$idcard = substr($idcard, 0, 6) . '19'. substr($idcard, 6, 9);
　}
　}

$idcard = $idcard . idcard_verify_number($idcard);

return $idcard;
}

// 18-digit ID card verification code validity check
function idcard_checksum18($idcard){
　if (strlen($idcard) != 18){ return false; }
$idcard_base = substr($idcard, 0, 17);
if (idcard_verify_number($idcard_base) != strtoupper(substr($idcard, 17, 1))){
return false;
}else{
return true;
}
}
?＞
The $idcard_base refers to the base code in the ID card. The base code is only found in the 18-digit ID card, which is the 18-digit identity. The first 17 digits of the certificate, and the last digit is called the verification code
Generally, there is no need to call idcard_verify_number() directly when using it. Most of the usual applications use the latter two functions, and these functions do not care about the ID card string. Format issues, please check the format yourself before calling.