JSFiddle - React, Tailwind, and code Playground

HTML

<div>
    <span>Conditional: </span><span id="conditional"></span>
</div>
<div>
    <span>Modulo: </span><span id="modulo"></span>
</div>

JavaScript

var iterations = 10000000,
    threshold = 100;

function getTime() {
    var date = new Date();
    return date.getTime();
}

function conditionalTest() {
    var element = document.getElementById('conditional'),
        x = 0,
        time = getTime();
    for (var i = 0; i < iterations; i++) {
        x++;
        if (x == threshold) {
            x = 0;
        }
    }
    time = (getTime() - time);
    element.innerText = time + ' ' + x;
}

function moduloTest() {
    var element = document.getElementById('modulo'),
        x = 0,
        time = getTime();
    for (var i = 0; i < iterations; i++) {
        x = (x + 1) % threshold;
    }
    time = (getTime() - time);
    element.innerText = time + ' ' + x;
}

conditionalTest();
moduloTest();