JSFiddle - React, Tailwind, and code Playground

HTML

<div class="current"></div>
<div class="current"></div>
<div class="current"></div>
<div class="current"></div>

CSS

div {
    width: 100px;
    height: 100px;
}

.current {
    border: 1px solid #ff0000;
}

.none {
    border: 1px solid #0000ff;
}

JavaScript

var els = document.getElementsByClassName('current');

setTimeout(function () {
    while (els.length) {
        els[0].className = 'none';
    }
}, 1500);