Javascript Event Countdown Timer

jQuery Script

<script>
var clockModule = (function($){
    
    // Clock
    function getTimeRemaining(endtime)
    {
        var t = Date.parse(endtime) - Date.parse(new Date());
        var seconds = Math.floor((t / 1000) % 60);
        var minutes = Math.floor((t / 1000 / 60) % 60);
        var hours = Math.floor((t / (1000 * 60 * 60)) % 24);
        var days = Math.floor(t / (1000 * 60 * 60 * 24));
        return {
            
            'total': t,
            'days': days,
            'hours': hours,
            'minutes': minutes,
            'seconds': seconds
        }
    }
    
    function initializeClock( id, endtime )
    {
        var clock = document.getElementById(id);
        var daysSpan = clock.querySelector('.days');
        var hoursSpan = clock.querySelector('.hours');
        var minutesSpan = clock.querySelector('.minutes');
        var secondsSpan = clock.querySelector('.seconds');
        
        function updateClock()
        {
            var 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();
        var timeinterval = setInterval(updateClock, 1000);
    }
    
    return {
        init: function( id, endtime )
        {
            initializeClock( id, endtime );
        }
    }

})(jQuery);
</script>

HTML Markup

<div id="clockdiv">
    <div>
        <span class="days"></span>
        <div class="smalltext">Days</div>
    </div>
    <div>
        <span class="hours"></span>
        <div class="smalltext">Hours</div>
    </div>
    <div>
        <span class="minutes"></span>
        <div class="smalltext">Minutes</div>
    </div>
    <div>
        <span class="seconds"></span>
        <div class="smalltext">Seconds</div>
    </div>
</div>
<script>clockModule.init('clockdiv', 'June 20 2016 00:05:00 GMT-0600');</script>