日期结果格式错误

我尝试在我的网站上设置计时器。

现在我必须用"End Day"减去"Now Day"，像这样:-

  var end = new Date( 2014 , 08 , 16 , 14 , 20 , 0 );

var _second = 1000;
var _minute = _second * 60;
var _hour = _minute * 60;
var _day = _hour * 24;
var timer;
function showRemaining() {
    var now = new Date();
    var distance = end - now;

    if (distance < 0) {
        clearInterval(timer);
        document.getElementById('d').innerHTML = '-';
        document.getElementById('m').innerHTML = '-';
        document.getElementById('h').innerHTML = '-';
        document.getElementById('s').innerHTML = '-';
        return;
    }
    var days = Math.floor(distance / _day);
    var hours = Math.floor((distance % _day) / _hour);
    var minutes = Math.floor((distance % _hour) / _minute);
    var seconds = Math.floor((distance % _minute) / _second);
    if(days)
    {
        document.getElementById('d').innerHTML = days;
        $("#d").parent('li').show();
    }
    document.getElementById('h').innerHTML = hours;
    document.getElementById('m').innerHTML = minutes;
    document.getElementById('s').innerHTML = seconds;
    $(".timers").css({'visibility':'visible'});
}
timer = setInterval(showRemaining, 1000);

这个操作的结果应该是1天，但是它显示给我31天!!

我试着提醒

var end = new Date( 2014 , 08 , 16 , 14 , 20 , 0 );

它显示我Tue sep 16 2014 14:20:00 GMT +0300 (Jerusalem Daylight Time)

它的错误，它必须像Tue Agu 16 2014 14:20:00 GMT +0300 (Jerusalem Daylight Time)

为什么! !