js時間戳轉換日期

//js時間戳轉換日期
function formatDate(now) {
    var year=now.getFullYear();
    var month=now.getMonth()+1;
    var date=now.getDate();
    var hour=now.getHours();
    var minute=now.getMinutes();
    var second=now.getSeconds();
    return year+"-"+month+"-"+date+" "+hour+":"+minute+":"+second;
}

var d=new Date(時間戳（毫秒）);
alert(formatDate(d));