倒计时（如：0天0小时5分钟）

 public function getCountdownTime($value)
    {
        $countdown = array('days' => 0, 'hours' => 0, 'minutes' => 0, 'seconds' => 0);
        $remain = $value - time();
        if ($remain <= 0) {
            return $countdown;
        }
        $countdown['days'] = intval($remain / 86400);
        $remain            = $remain - 86400 * $countdown['days'];
        $countdown['hours'] = intval($remain / 3600);
        $remain             = $remain - 3600 * $countdown['hours'];
        $countdown['minutes'] = intval($remain / 60);
        $remain               = $remain - 60 * $countdown['minutes'];
        $countdown['seconds'] = $remain;
        return $countdown;
    }