//判断date1是否大于date2+day
function compareDate(date1, date2, day) {
    var startdate = new Date((date1).replace(/-/g, "/"));
    var enddate = date2 == null ? new Date() : new Date((date2).replace(/-/g, "/"));
    if (!(getFormattedDate(startdate) >= getFormattedDate(enddate.addDays(day)))) {
        return false;
    }
    else {
        return true;
    }
}

Date.prototype.addSeconds = function (seconds) {
    this.setSeconds(this.getSeconds() + seconds);
    return this;
};

Date.prototype.addMinutes = function (minutes) {
    this.setMinutes(this.getMinutes() + minutes);
    return this;
};

Date.prototype.addHours = function (hours) {
    this.setHours(this.getHours() + hours);
    return this;
};

Date.prototype.addDays = function (days) {
    this.setDate(this.getDate() + days);
    return this;
};

Date.prototype.addWeeks = function (weeks) {
    this.addDays(weeks * 7);
    return this;
};

Date.prototype.addMonths = function (months) {
    var dt = this.getDate();

    this.setMonth(this.getMonth() + months);
    var currDt = this.getDate();

    if (dt !== currDt) {
        this.addDays(-currDt);
    }

    return this;
};

Date.prototype.addYears = function (years) {
    var dt = this.getDate();

    this.setFullYear(this.getFullYear() + years);

    var currDt = this.getDate();

    if (dt !== currDt) {
        this.addDays(-currDt);
    }

    return this;
};
function getFormattedDate(date) {
    var year = date.getFullYear();
    var month = (1 + date.getMonth()).toString();
    month = month.length > 1 ? month : ‘0‘ + month;
    var day = date.getDate().toString();
    day = day.length > 1 ? day : ‘0‘ + day;
    return year + ‘/‘ + month + ‘/‘ + day;
}