JSFiddle - React, Tailwind, and code Playground

by jfriend00

HTML

<div>
    <div id="test"></div>
    <div></div>
</div>
<div id="result"></div>

JavaScript

function findElementPercentage(target) {
    var all = document.body.getElementsByTagName("*");
    for (var i = 0; i < all.length; i++) {
        if (all[i] === target) {
            return (i/all.length) * 100;
        }
    }
}

var pos = findElementPercentage(document.getElementById("test"));
document.getElementById("result").innerHTML = pos;