<div id="countdown" class="countdown"></div>
<script type="text/javascript">
 function countdown() {
     var startTimestamp = 1383553207;
     var intervalTimestamp = 4 * 24 * 60 * 60;
     var dateObj = new Date();
     var time = dateObj.getTime().toString().substring(0, 10);
     for (i = 1;; i++) {
         var remainingTime = (startTimestamp + intervalTimestamp * i) - time;
         if (remainingTime > 0) break;
     }
     var d = Math.floor(remainingTime / (24 * 60 * 60));
     var H = Math.floor(remainingTime / (60 * 60) % 24);
     var i = Math.floor(remainingTime / 60 % 60);
     var s = Math.floor(remainingTime % 60);
     var mi = 999 - dateObj.getMilliseconds();
     if (mi < 10) {
         mi = '00' + mi;
     } else if (mi < 100) {
         mi = '0' + mi;
     }
     var countdown = '<strong>' + d + '</strong>d: <strong>' + H + '</strong>h: <strong>' + i + '</strong>m: <strong>' + s + '</strong>s <em>' + mi + '</em>';
     document.getElementById('countdown').innerHTML = countdown + '<sub>①</sub>';
     setTimeout('countdown()', 1);
 }
 countdown();
</script>