javascript 倒计时

// 倒计时var fnTimeCountDown = function (time) {    var time = new Date(time).getTime() - new Date().getTime(), // 倒计时时间转变为毫秒数        days, hours, min, sec, temp;    if (time <= 0) {        return null;    }    days = Math.floor(time / (24*3600*1000));    temp = time % (24*3600*1000); // 不够天的转换成小时    hours = Math.floor(temp / (3600*1000));    temp = temp % (3600*1000);  // 剩余的分钟数    min = Math.floor(temp / (60*1000));    temp = temp % (60*1000);    sec = Math.floor(temp / (1000));    // 格式化："05"    var zero = function (n) {        var n = parseInt(n, 10);        if (n > 0) {            if (n <= 9) {                n = "0" + n;            }            return n;        } else {            return "00";        }    };    return {        days: days,        hours: zero(hours),        min: zero(min),        sec: zero(sec)    };};var future = "2014/01/01 00:00",     countobj = null,    timer = null,    countdown = function (time, callback) {        // 倒计时数据对象：countobj        countobj = fnTimeCountDown(time);        callback && callback(countobj);        if (countobj) {            timer = setTimeout(function () {                countdown(time, callback);            }, 1000);        } else {            // 倒计时结束            clearTimeout(timer);        }    };setTimeout(function () {    countdown(future, function (obj) {            if (obj) {            // 倒计时应用            console.log(obj);        } else {            // 倒计时结束            console.log("countdown over!");        }    });}, 0);