Timer Tutorial Development Tutorials, Guides & Insights

Next, we need a function to update the timer every second:

function initializeClock(id, endtime) {
    const clock = document.getElementById(id);
    const daysSpan = clock.querySelector('.days');
    const hoursSpan = clock.querySelector('.hours');
    const minutesSpan = clock.querySelector('.minutes');
    const secondsSpan = clock.querySelector('.seconds');

    function updateClock() {
        const t = getTimeRemaining(endtime);

        daysSpan.innerHTML = t.days;
        hoursSpan.innerHTML = ('0' + t.hours).slice(-2);
        minutesSpan.innerHTML = ('0' + t.minutes).slice(-2);
        secondsSpan.innerHTML = ('0' + t.seconds).slice(-2);

        if (t.total <= 0) {
            clearInterval(timeinterval);
        }
    }

    updateClock();
    const timeinterval = setInterval(updateClock, 1000);
}