window.onload = function() { // Month Day, Year Hour:Minute:Second, id-of-element-container countUpFromTime("Oct 1, 2016 12:00:00", 'co2'); // ****** Change this line! }; function countUpFromTime(countFrom, id) { countFrom = new Date(countFrom).getTime(); var now = new Date(), countFrom = new Date(countFrom), timeDifference = (now - countFrom); var secondsInADay = 60 * 60 * 1000 * 24, secondsInAHour = 60 * 60 * 1000; days = Math.abs(timeDifference * ((0.0012/1000))); ddays = Math.floor(timeDifference); hours = Math.floor((timeDifference % (secondsInADay)) / (secondsInAHour) * 1); mins = Math.floor(((timeDifference % (secondsInADay)) % (secondsInAHour)) / (60 * 1000) * 1); secs = Math.floor((((timeDifference % (secondsInADay)) % (secondsInAHour)) % (60 * 1000)) / 1000 * 1); var idEl = document.getElementById(id); idEl.getElementsByClassName('days')[0].innerHTML = days.toFixed(4).replace('.', ','); // idEl.getElementsByClassName('hours')[0].innerHTML = hours; // idEl.getElementsByClassName('minutes')[0].innerHTML = mins; // idEl.getElementsByClassName('seconds')[0].innerHTML = secs.toFixed(4); clearTimeout(countUpFromTime.interval); countUpFromTime.interval = setTimeout(function(){ countUpFromTime(countFrom, id); }, 20); }