var target_date = new Date("Mar 3, 2014").getTime();
var days, hours, minutes, seconds;
var countdown = document.getElementById("countdown");
setInterval(function () {
var current_date = new Date().getTime();
var seconds_left = (target_date - current_date) / 1000;
days = parseInt(seconds_left / 86400);
seconds_left = seconds_left % 86400;
hours = parseInt(seconds_left / 3600);
seconds_left = seconds_left % 3600;
minutes = parseInt(seconds_left / 60);
seconds = parseInt(seconds_left % 60);
countdown.innerHTML = days + "d " + hours + "h "
+ minutes + "m " + seconds + "s ";
}, 1000);