JSFiddle - React, Tailwind, and code Playground

HTML

<span id="countdown-1">86405</span>

JavaScript

secs = parseInt(document.getElementById('countdown-1').innerHTML,10);
setTimeout("countdown('countdown-1',"+secs+")", 1000);

function countdown(id, timer){
    function pad(num) {
        return num > 9 ? num : '0'+num;
    };
    timer--;
    days = Math.floor( timer / 86400 ),
	hours = Math.floor( timer / 3600 ),
	mins = Math.floor( timer / 60 ),
	secs = Math.floor( timer ),
 
	dd = days,
	hh = hours - days * 24,
	mm = mins - hours * 60,
	ss = secs - mins * 60;

    if ( dd < 1 ) {
        clock = pad(hh) + ':' + pad(mm) + ':' + pad(ss) ;
    } else {
        clock = dd + ' days ' + pad(hh) + ':' + pad(mm) + ':' + pad(ss) ;
    }
    document.getElementById(id).innerHTML = clock;
    if ( timer > 0 ) {
        setTimeout("countdown('" + id + "'," + timer + ")", 1000);
    } else {
        window.location.reload(forceGet);
    }
}