JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.2.4/jquery.min.js"></script>
        <script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/js-cookie/2.1.2/js.cookie.js"></script>

           
           <a class="close" id="closeAdvertistement" onclick="CloseCookieAdvertisement()">CLOSE</a>

JavaScript

$(document).ready(function () {

    //Check for cookie. if it doesnt exist, create it
    var cookie = Cookies.get("Advertisement");
    alert(cookie);
    if (cookie == "undefined" || cookie == null || cookie == "" || cookie == "null") {
        CreateCookieAdvertisement();
    }

    //If cookie is closed, hide advertisement
    if (cookie == "closed") {
        $("#slidebox").addClass("HIDE");
    }

});

function CreateCookieAdvertisement() {
    alert("Creating cookie function");
    Cookies.set("Advertisement", "open");
}

function CloseCookieAdvertisement() {
    Cookies.remove('Advertisement');
    Cookies.set('Advertistement', 'closed');
}