JSFiddle - React, Tailwind, and code Playground

HTML

<script src="http://jquery.bassistance.de/validate/jquery.validate.js"></script>
<form id="myform" method="post">
        <select id="id_deals-0-currency" class="required" name="deals_0_currency">
        <option value="">---------</option>
        <option selected="selected" value="1">USD - $</option>
        <option value="2">EUR - €</option>
        </select>
</form>

JavaScript

$(function() {
    $.validator.addMethod("valueNotEquals", function(value, element, arg) {
        return arg != value;
    }, "Value must not equal arg.");


    $("#myform").validate({
        rules: {
            deals_0_currency: {
                valueNotEquals: ""
            }
        },
        messages: {
            deals_0_currency: {
                valueNotEquals: "Please select an item!"
            }
        }

    });

    $('#id_deals-0-currency').on('change', function() { alert('hi. we are about to validate on a change.'); $('#myform').valid(); });
});