JSFiddle - React, Tailwind, and code Playground

HTML

<html>
    <body>
    <div id="theme">You have selected the <div id="theme_title">x</div> Theme</div>
        <div class="container_16" id="themebg">
        <div class="grid_16 slider-wrapper">
        <ul class="s-thumbs">
                    <li class="Default"> <a href=""><img src="/styles/image/thumbs/default.png" alt="" /></a>Default</li>
                    <li class="Hatchery"> <a href=""><img src="/styles/image/thumbs/hatchery.png" alt="" /></a>Hatchery</li>
</ul>
</div>
    </body></html>

JavaScript

$(document).ready(function() {

    $('ul.s-thumbs li').on('click', function() {
        var getClass = $(this).attr('class');
        $("#theme_title").text(getClass);
    });

});