jQuery validate copy address details

HTML

<script src="http://ajax.aspnetcdn.com/ajax/jquery.validate/1.8.1/jquery.validate.min.js"></script>
<!doctype html>
<html class="no-js" lang="en">
    <head>
        <meta charset="utf-8">
        <title></title>
    </head>
    <body>
        
        <form action="#" method="post" class="validate">
           
            <fieldset>    
               <legend>Booking Address</legend>    
              
               <p><label for="delivery_address1">Address<sup>*</sup></label> 
                <input type="text" value="" name="order_delivery_address1" class="required" id="delivery_address1" /></p>
                
               <p><label for="delivery_town">Town<sup>*</sup></label> 
                <input type="text" value="" name="order_delivery_town" class="required" id="delivery_town" /></p>
                
               <p><label for="delivery_county">County</label> 
                <input type="text" value="" name="order_delivery_county" id="delivery_county" /></p>
                
               <p><label for="delivery_postcode">Postcode<sup>*</sup></label> 
                <input type="text" value="" name="order_delivery_postcode" class="required" id="delivery_postcode" /></p>
                
               <p><label for="delivery_country">Country</label> 
               <select name="order_delivery_country" id="delivery_country" class="valid">
                   <option value="">--- Select ---</option>
                    <option value="1">Afghanistan</option>
                    <option value="2">Aland Islands</option>
                    <option value="3">Albania</option>
                    <option value="4">Algeria</option>
                    <option value="310">American Samoa</option>
                    <option value="5">Andorra</option>
                    <option value="6">Angola</option>
                    <option value="7">Anguilla</option>
                    <option value="8">Antarctica</option>
                    <option...

CSS

fieldset {
    border: 2px solid blue;
    padding: 10px ;
}
.error {
    color: red;
}

JavaScript

var validate = $(".validate");
if (validate.length) {
    validate.validate({
        errorPlacement: function(error, element) {
            error.insertAfter(element.parent());
        }
    });
}

$("#copyDetails").click(function() {
    if ($(this).attr("checked")) {
        $("#billing_address1").attr('value', $("#delivery_address1").attr("value"));
        $("#billing_town").attr('value', $("#delivery_town").attr("value"));
        $("#billing_county").attr('value', $("#delivery_county").attr("value"));
        $("#billing_postcode").attr('value', $("#delivery_postcode").attr("value"));
        $("#billing_country").attr('value', $("#delivery_country").attr("value"));
    } else {
        $("#billing_address1").attr('value', '');
        $("#billing_town").attr('value', '');
        $("#billing_county").attr('value', '');
        $("#billing_postcode").attr('value', '');
        $("#billing_country").attr('value', '');
    }

    validate.resetForm();
});