JSFiddle - React, Tailwind, and code Playground

HTML

<div id="timer"></div>

JavaScript

function countdown(startDate, el)
{
    var hour = startDate.getUTCHours();
    var min = startDate.getUTCMinutes();   
    var interval;
    
    var f = function(){
        if (min == -1) {
            min = 59;
            hour--;
        }
        
        if (min < 10) {
            min = "0" + min;
        }
        
        var time = hour + ':' + min;
        el.innerHTML = time;
        
        if (hour == 0 && min == 00) {
            clearInterval(interval);
        }
        
        min--;
    };
    
    f();
   	
    interval = setInterval(f, 60 * 1000);   
}

countdown(new Date(), document.getElementById('timer'));