<?php
function validateCC($cc_num, $type) {

	if($type == "American") {
	$denum = "American Express";
	} elseif($type == "Dinners") {
	$denum = "Diner's Club";
	} elseif($type == "Discover") {
	$denum = "Discover";
	} elseif($type == "Master") {
	$denum = "Master Card";
	} elseif($type == "Visa") {
	$denum = "Visa";
	}

	if($type == "American") {
	$pattern = "/^([34|37]{2})([0-9]{13})$/";//American Express
	if (preg_match($pattern,$cc_num)) {
	$verified = true;
	} else {
	$verified = false;
	}


	} elseif($type == "Dinners") {
	$pattern = "/^([30|36|38]{2})([0-9]{12})$/";//Diner's Club
	if (preg_match($pattern,$cc_num)) {
	$verified = true;
	} else {
	$verified = false;
	}


	} elseif($type == "Discover") {
	$pattern = "/^([6011]{4})([0-9]{12})$/";//Discover Card
	if (preg_match($pattern,$cc_num)) {
	$verified = true;
	} else {
	$verified = false;
	}


	} elseif($type == "Master") {
	$pattern = "/^([51|52|53|54|55]{2})([0-9]{14})$/";//Mastercard
	if (preg_match($pattern,$cc_num)) {
	$verified = true;
	} else {
	$verified = false;
	}


	} elseif($type == "Visa") {
	$pattern = "/^([4]{1})([0-9]{12,15})$/";//Visa
	if (preg_match($pattern,$cc_num)) {
	$verified = true;
	} else {
	$verified = false;
	}

	}

	if($verified == false) {
	//Do something here in case the validation fails
	echo "Credit card invalid. Please make sure that you entered a valid <em>" . $denum . "</em> credit card ";

	} else { //if it will pass...do something
	echo "Your <em>" . $denum . "</em> credit card is valid";
	}


}
echo validateCC("4111111111111111", "Visa");
?>

http://www.roscripts.com/How_to_validate_credit_card_numbers-106.html

Validate the credit card number is valid or not

Credit card validation in php

php, validation

PHP