JSFiddle - React, Tailwind, and code Playground

HTML

<p id="countdown2"></p>

CSS

p {
    color: #1B232F;
    font-family: Verdana, Arial, sans-serif;
    font-size: 18px;
    font-weight: bold;
    text-decoration: none;
}

JavaScript

countdown("countdown2", 50, 0);
function countdown(element, minutes, seconds) {
    var time = minutes*60 + seconds;
    var interval = setInterval(function() {
        var el = document.getElementById(element);
        if(time == 0) {
            el.innerHTML = "countdown's over!";    
            clearInterval(interval);
            return;
        }
        var minutes = Number.floor( time / 60 );
        if (minutes < 10) minutes = "0" + minutes;
        var seconds = time % 60;
        if (seconds < 10) seconds = "0" + seconds; 
        var text = minutes + ':' + seconds;
        el.innerHTML = text;
        time--;
    }, 1000);
}