JSFiddle - React, Tailwind, and code Playground

HTML

<div>
<ul id="1">
    <li class="active">Popular</li>
    <li>New Addition</li>
</ul>
</div>
<div>
<ul id="2">
    <li>Popular</li>
    <li>New Addition</li>
</ul>
</div>
...
<div>
<ul id="n">
    <li>Popular</li>
    <li>New Addition</li>
</ul>
</div>

CSS

.active {
    background-color: red;
}

JavaScript

var tabs = document.getElements("li");
tabs.addEvent('click', function() {
    tabs.removeClass('active');
    this.addClass('active');
});