好似寫的有點復雜。把倒計時時間，重置時間，計時器的偏差都加上了。

var s = 1000,

    m = 60 * s,

    h = 60 * m,

    d = 24 * h,

    tick_time = 1000,

    timezone = new Date().getTimezoneOffset() * m;

var getDayTime = function(t) {

  t = t.split(':');

  return t[0] * h + t[1] * m;

}

var getNextClock = function(clockTime, resetTime, now) {

  var result = now_d = parseInt(now / d, 10) * d + timezone;

  now_d_t = now - now_d;

  if (now_d_t > resetTime) {

    result += d;

  }

  return result + clockTime;

};

var before = 0,

  resetTime = getDayTime('00:00'),

  clock24 = getDayTime('10:00');

var tickHandler = function() {

  var now = Date.now();

  if (now - before > tick_time) {

    var nextClock = getNextClock(clock24, resetTime, now);

    var diff = nextClock - now;

    var floor = Math.floor;

    var diif_readable = [

      floor(diff / d),

      floor((diff % d) / h),

      floor((diff % h) / m),

      floor((diff % m) / s)

    ];

    console.log(diif_readable);

    before = now;

  }

};

var handler = setInterval(tickHandler, tick_time/10);

tickHandler();