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; } return false;}
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