php信用卡卡号验证函数

 

介绍一个php信用卡卡号验证函数，可以验证一个卡号是否是信用卡。

 

function validateCard ($cardnumber){

    $cardnumber = preg_replace ("/\D|\s/","", $cardnumber);

    $cardlength = strlen($cardnumber);if($cardlength !=0){

        $parity = $cardlength %2;

        $sum =0;for($i=0; $i<$cardlength; $i++){

            $digit = $cardnumber[$i];if($i %2== $parity) $digit = $digit *2;if($digit >9) $digit = $digit -9;

            $sum = $sum + $digit;}

        $valid =($sum %10==0);return $valid;}returnfalse;}

 

 

文章摘自：php信用卡卡号验证函数