JSFiddle - React, Tailwind, and code Playground

HTML

<div class="Visitor" id="ONE" name="Here">1</div>
<div class="Visitor" id="TWO" name="We">2</div>
<div class="Visitor" id="THREE" name="Go">3</div>

JavaScript

var elements = document.getElementsByClassName('Visitor');

for (var k in elements) {
    console.log("k = " + k);
}