js多个倒计时并存

function countDown(time, fn) {    var maxtime = (new Date(time) - new Date()) / 1000;//剩余秒    var timer = setInterval(function () {        if (maxtime >= 0) {            var dd = parseInt(maxtime / 60 / 60 / 24, 10);//计算剩余的天数              var hh = parseInt(maxtime / 60 / 60 % 24, 10);//计算剩余的小时数              var mm = parseInt(maxtime / 60 % 60, 10);//计算剩余的分钟数              var ss = parseInt(maxtime % 60, 10);//计算剩余的秒数              hh = checkTime(hh);            mm = checkTime(mm);            ss = checkTime(ss);            msg = "剩余时间 " + dd + "天" + hh + "时" + mm + "分" + ss + "秒";            fn(msg);            --maxtime;        }        else {            clearInterval(timer);            fn("已结束");        }    }, 1000);}function checkTime(i) {    if (i < 10) {        i = "0" + i;    }    return i;}/*使用方法<script type="text/javascript">                    countDown('2015-5-29 10:40:44', function (msg) {                        $('#time_1').text(msg);                    });                </script>                */