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>
                */