Usman Y回答的Swift 2.1版本。 使用print语句来验证，因此调用某个字符串值

print(self.validateCardType(self.creditCardField.text!))

func validateCardType(testCard: String) -> String {

    let regVisa = "^4[0-9]{12}(?:[0-9]{3})?$"
    let regMaster = "^5[1-5][0-9]{14}$"
    let regExpress = "^3[47][0-9]{13}$"
    let regDiners = "^3(?:0[0-5]|[68][0-9])[0-9]{11}$"
    let regDiscover = "^6(?:011|5[0-9]{2})[0-9]{12}$"
    let regJCB = "^(?:2131|1800|35\\d{3})\\d{11}$"


    let regVisaTest = NSPredicate(format: "SELF MATCHES %@", regVisa)
    let regMasterTest = NSPredicate(format: "SELF MATCHES %@", regMaster)
    let regExpressTest = NSPredicate(format: "SELF MATCHES %@", regExpress)
    let regDinersTest = NSPredicate(format: "SELF MATCHES %@", regDiners)
    let regDiscoverTest = NSPredicate(format: "SELF MATCHES %@", regDiscover)
    let regJCBTest = NSPredicate(format: "SELF MATCHES %@", regJCB)


    if regVisaTest.evaluateWithObject(testCard){
        return "Visa"
    }
    else if regMasterTest.evaluateWithObject(testCard){
        return "MasterCard"
    }

    else if regExpressTest.evaluateWithObject(testCard){
        return "American Express"
    }

    else if regDinersTest.evaluateWithObject(testCard){
        return "Diners Club"
    }

    else if regDiscoverTest.evaluateWithObject(testCard){
        return "Discover"
    }

    else if regJCBTest.evaluateWithObject(testCard){
        return "JCB"
    }

    return ""

}

只需一点点的勺子喂养:

$("#CreditCardNumber").focusout(function () {


        var regVisa = /^4[0-9]{12}(?:[0-9]{3})?$/;
        var regMasterCard = /^5[1-5][0-9]{14}$/;
        var regAmex = /^3[47][0-9]{13}$/;
        var regDiscover = /^6(?:011|5[0-9]{2})[0-9]{12}$/;

        if (regVisa.test($(this).val())) {
            $("#CCImage").html("<img height='40px' src='@Url.Content("~/images/visa.png")'>");          

        }

        else if (regMasterCard.test($(this).val())) {
        $("#CCImage").html("<img height='40px' src='@Url.Content("~/images/mastercard.png")'>");

        }

        else if (regAmex.test($(this).val())) {

           $("#CCImage").html("<img height='40px' src='@Url.Content("~/images/amex.png")'>");

        }
         else if (regDiscover.test($(this).val())) {

           $("#CCImage").html("<img height='40px' src='@Url.Content("~/images/discover.png")'>");

        }
        else {
        $("#CCImage").html("NA");

        }

    });

Stripe提供了这个很棒的javascript库来检测卡片方案。让我添加一些代码片段，并向您展示如何使用它。

首先包括它到你的网页作为

<script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/jquery.payment/1.2.3/jquery.payment.js " ></script>

其次，利用功能cardType来检测卡片方案。

$(document).ready(function() {              
            var type = $.payment.cardType("4242 4242 4242 4242"); //test card number
            console.log(type);                                   
}); 

这里有更多示例和演示的参考链接。

Stripe博客的jquery.payment.js Github库

anatoly用PHP回答:

 public static function detectCardType($num)
 {
    $re = array(
        "visa"       => "/^4[0-9]{12}(?:[0-9]{3})?$/",
        "mastercard" => "/^5[1-5][0-9]{14}$/",
        "amex"       => "/^3[47][0-9]{13}$/",
        "discover"   => "/^6(?:011|5[0-9]{2})[0-9]{12}$/",
    );

    if (preg_match($re['visa'],$num))
    {
        return 'visa';
    }
    else if (preg_match($re['mastercard'],$num))
    {
        return 'mastercard';
    }
    else if (preg_match($re['amex'],$num))
    {
        return 'amex';
    }
    else if (preg_match($re['discover'],$num))
    {
        return 'discover';
    }
    else
    {
        return false;
    }
 }

// abobjects.com, parvez ahmad ab bulk mailer
use below script

function isValidCreditCard2(type, ccnum) {
       if (type == "Visa") {
          // Visa: length 16, prefix 4, dashes optional.
          var re = /^4\d{3}?\d{4}?\d{4}?\d{4}$/;
       } else if (type == "MasterCard") {
          // Mastercard: length 16, prefix 51-55, dashes optional.
          var re = /^5[1-5]\d{2}?\d{4}?\d{4}?\d{4}$/;
       } else if (type == "Discover") {
          // Discover: length 16, prefix 6011, dashes optional.
          var re = /^6011?\d{4}?\d{4}?\d{4}$/;
       } else if (type == "AmEx") {
          // American Express: length 15, prefix 34 or 37.
          var re = /^3[4,7]\d{13}$/;
       } else if (type == "Diners") {
          // Diners: length 14, prefix 30, 36, or 38.
          var re = /^3[0,6,8]\d{12}$/;
       }
       if (!re.test(ccnum)) return false;
       return true;
       /*
       // Remove all dashes for the checksum checks to eliminate negative numbers
       ccnum = ccnum.split("-").join("");
       // Checksum ("Mod 10")
       // Add even digits in even length strings or odd digits in odd length strings.
       var checksum = 0;
       for (var i=(2-(ccnum.length % 2)); i<=ccnum.length; i+=2) {
          checksum += parseInt(ccnum.charAt(i-1));
       }
       // Analyze odd digits in even length strings or even digits in odd length strings.
       for (var i=(ccnum.length % 2) + 1; i<ccnum.length; i+=2) {
          var digit = parseInt(ccnum.charAt(i-1)) * 2;
          if (digit < 10) { checksum += digit; } else { checksum += (digit-9); }
       }
       if ((checksum % 10) == 0) return true; else return false;
       */

    }
jQuery.validator.addMethod("isValidCreditCard", function(postalcode, element) { 
    return isValidCreditCard2($("#cardType").val(), $("#cardNum").val()); 

}, "<br>credit card is invalid");


     Type</td>
                                          <td class="text">&nbsp; <form:select path="cardType" cssclass="fields" style="border: 1px solid #D5D5D5;padding: 0px 0px 0px 0px;width: 130px;height: 22px;">
                                              <option value="SELECT">SELECT</option>
                                              <option value="MasterCard">Mastercard</option>
                                              <option value="Visa">Visa</option>
                                               <option value="AmEx">American Express</option>
                                              <option value="Discover">Discover</option>
                                            </form:select> <font color="#FF0000">*</font> 

$("#signupForm").validate({

    rules:{
       companyName:{required: true},
       address1:{required: true},
       city:{required: true},
       state:{required: true},
       zip:{required: true},
       country:{required: true},
       chkAgree:{required: true},
       confPassword:{required: true},
       lastName:{required: true},
       firstName:{required: true},
       ccAddress1:{required: true},
       ccZip:{         
           postalcode : true
       },
       phone:{required: true},
       email:{
           required: true,
           email: true
           },
       userName:{
           required: true,
           minlength: 6
           },
       password:{
           required: true,
           minlength: 6
           },          
       cardNum:{           
            isValidCreditCard : true
       },

看看这个:

http://www.breakingpar.com/bkp/home.nsf/0/87256B280015193F87256CC70060A01B

function isValidCreditCard(type, ccnum) {
    /* Visa: length 16, prefix 4, dashes optional.
    Mastercard: length 16, prefix 51-55, dashes optional.
    Discover: length 16, prefix 6011, dashes optional.
    American Express: length 15, prefix 34 or 37.
    Diners: length 14, prefix 30, 36, or 38. */

    var re = new Regex({
        "visa": "/^4\d{3}-?\d{4}-?\d{4}-?\d",
        "mc": "/^5[1-5]\d{2}-?\d{4}-?\d{4}-?\d{4}$/",
        "disc": "/^6011-?\d{4}-?\d{4}-?\d{4}$/",
        "amex": "/^3[47]\d{13}$/",
        "diners": "/^3[068]\d{12}$/"
    }[type.toLowerCase()])

    if (!re.test(ccnum)) return false;
    // Remove all dashes for the checksum checks to eliminate negative numbers
    ccnum = ccnum.split("-").join("");
    // Checksum ("Mod 10")
    // Add even digits in even length strings or odd digits in odd length strings.
    var checksum = 0;
    for (var i = (2 - (ccnum.length % 2)); i <= ccnum.length; i += 2) {
        checksum += parseInt(ccnum.charAt(i - 1));
    }
    // Analyze odd digits in even length strings or even digits in odd length strings.
    for (var i = (ccnum.length % 2) + 1; i < ccnum.length; i += 2) {
        var digit = parseInt(ccnum.charAt(i - 1)) * 2;
        if (digit < 10) { checksum += digit; } else { checksum += (digit - 9); }
    }
    if ((checksum % 10) == 0) return true;
    else return false;
}