JSFiddle - React, Tailwind, and code Playground
HTML
<div id="clockdiv">
<div class="timerdays">
<span class="days" id="day"></span>
<div class="smalltext">Days</div>
</div>
<div class="timerdays">
<span class="hours" id="hour"></span>
<div class="smalltext">Hours</div>
</div>
<div class="timerdays">
<span class="minutes" id="minute"></span>
<div class="smalltext">Minutes</div>
</div>
<div class="timerdays">
<span class="seconds" id="second"></span>
<div class="smalltext">Seconds</div>
</div>
</div>
JavaScript
var deadline = new Date("May 1, 2019 03:30:00").getTime();
var x = setInterval(function()
{
var now = new Date().getTime();
var t = deadline - now;
var days = Math.floor(t / (1000 * 60 * 60 * 24));
var hours = Math.floor((t%(1000 * 60 * 60 * 24))/(1000 * 60 * 60));
var minutes = Math.floor((t % (1000 * 60 * 60)) / (1000 * 60));
var seconds = Math.floor((t % (1000 * 60)) / 1000);
document.getElementById("day").innerHTML =days ;
document.getElementById("hour").innerHTML =hours;
document.getElementById("minute").innerHTML = minutes;
document.getElementById("second").innerHTML =seconds;
if (t < 0)
{
clearInterval(x);
document.getElementById("demo").innerHTML = "TIME UP";
document.getElementById("day").innerHTML ='0';
document.getElementById("hour").innerHTML ='0';
document.getElementById("minute").innerHTML ='0' ;
document.getElementById("second").innerHTML = '0';
}
}, 1000);