JSFiddle - React, Tailwind, and code Playground

by David Thomas

HTML

<div id="container">
    <div class="item">...</div>
    <div class="item">...</div>
    <div class="item">...</div>
    <div class="item">...</div>
</div>

CSS

div {
    float: left;
    border: 1px solid #000;
    width: 5em;
    height: 5em;
}
div.random {
    border-color: #f00;
}
#container {
    height: auto;
    width: auto;
}

JavaScript

$('.item').eq(Math.floor(Math.random() * $('.item').length)).after('<div class="random"></div>');