Van ilyen app? 😂

enddate = new Date(2018, 5, 15);

kijelzo = document.getElementById('kijelzo');

window.setInterval(() => {

let sec = Math.floor((enddate - new Date()) / 1000);

var day = Math.floor(sec / 86400);

sec -= (day * 86400);

var hour = Math.floor(sec / 3600);

sec -= (hour * 3600);

var min = Math.floor(sec / 60);

sec -= (min * 60);

kijelzo.innerHTML = day + ' nap '+ hour + ' óra ' + min + ' perc ' + sec + ' másodperc ';

}, 1000);