JSFiddle - React, Tailwind, and code Playground

by Sub Lines

HTML

<div class="foo"></div>
<div class="foo"></div>
<div class="foo"></div>

CSS

.foo {
    height: 100px;
    width: 100px;
    background-color: red;
    background-size: 100% 100%;
}

JavaScript

function setBackground(urls, targetId) {
    setInterval(function() {
        var index = Math.floor(Math.random() * (urls.length));
        var target = document.getElementsByClassName(targetId);
        target.style.backgroundImage = "url(" + urls[index] + ")";
        
    }, 5000);
}

var urls = [
    'http://placekitten.com/g/150/150',
    'http://placekitten.com/g/200/200',
    'http://placekitten.com/g/250/250',
    'http://placekitten.com/g/300/300',
    'http://placekitten.com/g/400/400'
];

var target = "foo";

setBackground(urls, target);