function timediff($begin_time, $end_time)
{
    if ($begin_time < $end_time) {
        $starttime = $begin_time;
        $endtime = $end_time;
    } else {
        $starttime = $end_time;
        $endtime = $begin_time;
    }
 
    //計算天數
    $timediff = $endtime - $starttime;
    $days = intval($timediff / 86400);

    //計算小時數
    $remain = $timediff % 86400;
    $hours = intval($remain / 3600);

    //計算分鐘數
    $remain = $remain % 3600;
    $mins = intval($remain / 60);

    //計算秒數
    $secs = $remain % 60;
    $res = array("day" => $days, "hour" => $hours, "min" => $mins, "sec" => $secs);
    return $res;
}