JSFiddle - React, Tailwind, and code Playground

HTML

<div id="placeholder">
    
</div>

JavaScript

function randomString(length) {
    var chars = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXTZabcdefghiklmnopqrstuvwxyz'.split('');

    if (! length) {
        length = Math.floor(Math.random() * chars.length);
    }

    var str = '';
    for (var i = 0; i < length; i++) {
        str += chars[Math.floor(Math.random() * chars.length)];
    }
    return str;
}


var ph = document.getElementById('placeholder');

var rndId = randomString(8);
var div = document.createElement('div');
div.id = rndId;
div.innerHTML = "This div has the id:" + rndId;
ph.appendChild(div);