js获取两个日期的时间差

 function getinterval(start, end) {
            //两个日期对象，相差的毫秒数
            var interval = end - start;
            // 两个日期对象，相差的秒数
            // interval = interval / 1000;
            interval /= 1000;
            //求相差的天数/小时数/分钟数/秒数
            var day, hour, minute, second;
            day = math.round(interval / 60 / 60 / 24);
            hour = math.round(interval / 60 / 60 % 24);
            minute = math.round(interval / 60 % 60);
            second = math.round(interval % 60);
            return {
                day: day,
                hour: hour,
                minute: minute,
                second: second
            }
        }