下一周和上周的日历（Javascript）

Question

我使用此功能获取当前周

Date.prototype.getWeek = function(start)
{
    start = start || 0;
    today = new Date(this.setHours(0, 0, 0, 0));

    var day = today.getDay() - start;
    date = today.getDate() - day;

    var giorni = [];

    for (var i = 0;i<7;i++) {
        giorni.push(new Date(today.setDate(date+i)));
    }

    return  giorni;
}

var Dates = new Date().getWeek();

for(var i=0;i<7;i++){

    $scope.setts.push({
    "name":days[Dates[i].getDay()],
    "short": days[Dates[i].getDay()].substring(0,3),
    "data":Dates[i].toLocaleDateString().substring(0,5)
    });
}

并且本周工作正常，但是有下一个和prev方法的问题显示错误的日期。

$scope.prev = function () {

    var prev = new Date(today.setDate(date-7));
    var dates = prev.getWeek();

    $scope.setts = [];

    for(var i=0;i<7;i++) {

        $scope.setts.push({
            "name":days[dates[i].getDay()],
            "short": days[dates[i].getDay()].substring(0,3),
            "data":dates[i].toLocaleDateString().substring(0,5)
        });
    }
}

有什么建议吗？

周末愉快！