jquery.validate.js fecha de vencimiento cómo usar este método de agregar validador

Me di cuenta de esto y espero que pueda ayudar a alguien que intenta lograr lo mismo. Mi problema estaba tratando de usar jquery.validate.js y este $.validator.addMethod debajo. Tenía 2 campos para mi fecha de vencimiento, uno para el mes MM "01" y el otro para el año AAAA "<option value="12">2012</option>" así que los combiné en otra entrada de texto como MM/YYYY e hizo la validación en ese campo.

$.validator.addMethod(
        "ccexpdate",
    function (value, element) {
        // Initialize todays date   i.e start date
        var today = new Date();
        var startDate = new Date(today.getFullYear(),today.getMonth(),1,0,0,0,0);
        // Initialize End/Expiry date i.e. adding 10 years to expire
        var futureLimitDate= new Date(today.getFullYear()+10,today.getMonth(),1,0,0,0,0);
        var expDate = value;
        var expYearCheck='';
        // Check Date format
        var separatorIndex = expDate.indexOf('/');
        if(separatorIndex==-1)return false; // Return false if no / found
        var expDateArr=expDate.split('/'); 
        if(expDateArr.length>2)return false; // Return false if no num/num format found
        // Check Month for validity
        if(eval(expDateArr[0])<1||eval(expDateArr[0])>12)
        {
            //If month is not valid i.e not in range 1-12
            return false;
        }
        //Check Year for format YY or YYYY
        switch(expDateArr[1].length)
        {
            case 2:expYearCheck=2000+parseInt(expDateArr[1], 10);break; // If YY format convert it to 20YY to it
            case 4:expYearCheck=expDateArr[1];break; // If YYYY format assign it to check Year Var
            default:return false;break;
        }
        // Calculated new exp Date for ja  
        expDate=new Date(eval(expYearCheck),(eval(expDateArr[0])-1),1,0,0,0,0);
        if(Date.parse(startDate) <= Date.parse(expDate))
        {
            if(Date.parse(expDate) <= Date.parse(futureLimitDate))
            {
                // Date validated
                return true;    
            }else
            {
                // Date exceeds future date
                return false;
            }
        }else
        {
            // Date is earlier than todays date
            return false;
        }
    },
    "<br />Must be a valid Expiration Date."
    );

Tengo dos campos para mi fecha de vencimiento de la siguiente manera:

<select name="qbms_cc_expires_month" id="qbms_cc_expires_month">
<option value="01">01</option>
<option value="02">02</option>
<option value="03">03</option>
<option value="04">04</option>
<option value="05">05</option>
<option value="06">06</option>
<option value="07">07</option>
<option value="08">08</option>
<option value="09">09</option>
<option value="10">10</option>
<option value="11">11</option>
<option value="12">12</option>
</select>
<select name="qbms_cc_expires_year" id="qbms_cc_expires_year">
<option value="12">2012</option>
<option value="13">2013</option>
<option value="14">2014</option>
<option value="15">2015</option>
<option value="16">2016</option>
<option value="17">2017</option>
<option value="18">2018</option>
<option value="19">2019</option>
<option value="20">2020</option>
<option value="21">2021</option>
</select>

Agregué este campo al final de mi segunda selección:

<input type="text" name="qbmsCombined" id="qbmsCombined" value="" style="width:45px;height:16px;" readonly="readonly">

Y mi jQuery así

$().ready(function() {
    // combine exp date fields and validate new field
    $("#qbms_cc_expires_month,#qbms_cc_expires_year").change(function() {
       $("input[type='text'][name='qbmsCombined']").val($("#qbms_cc_expires_month").val() + '/' + $("#qbms_cc_expires_year").val());

    });
    // validate signup form on keyup and submit
    $("#checkoutForm").validate({
        rules: {
        qbms_cc_owner: {
                required: true
            },
        qbms_cc_number: {
                required: true,
                minlength: 13,
                maxlength: 16,
                creditcard: true
            },
            qbmsCombined: {
                ccexpdate: true
          },
          qbms_cc_cvv2: {
                required: true,
                minlength: 3,
                maxlength: 4
            },      
        },
        messages: {

            qbms_cc_owner: {
                required: "<br />Please enter the name on the Credit Card"
            },
            qbms_cc_number: {
                required: "<br />Please enter the Credit Card Number",
                minlength: "<br />Credit Card Number must be between 13 and 16 digits",
                maxlength: "<br />Credit Card Number is over 16 digits",
                creditcard: "<br />Credit Card Number is invalid"
            },
              qbms_cc_cvv2: {
                required: "<br />Please enter the Credit Card's Security Code",
                minlength: "<br />Credit Card's Security Code must be at least 3 digits",
                maxlength: "<br />Credit Card's Security Code must be 4 digits or less"
            },
        }

    });

    $('form#checkoutForm').submit(function(evt){
        if($('#checkoutForm').valid())
            return true
        else
        evt.preventDefault();
            return false;

    });
});