/**

* 日期范围工具类

*/

var dateRangeUtil = (function () {

    /***

    * 获得当前时间

    */

    this.getCurrentDate = function () {

        return new Date();

    };

    /***

    * 获得本周起止时间

    */

    this. 

    /***

    * 获得本月的起止时间

    */

    this.getCurrentMonth = function () {

        //起止日期数组

        var startStop = new Array();

        //获取当前时间

        var currentDate = this.getCurrentDate();

        //获得当前月份0-11

        var currentMonth = currentDate.getMonth();

        //获得当前年份4位年

        var currentYear = currentDate.getFullYear();

        //求出本月第一天

        var firstDay = new Date(currentYear, currentMonth, 1);

        //当为12月的时候年份需要加1

        //月份需要更新为0 也就是下一年的第一个月

        if (currentMonth == 11) {

            currentYear++;

            currentMonth = 0; //就为

        } else {

            //否则只是月份增加,以便求的下一月的第一天

            currentMonth++;

        }

        //一天的毫秒数

        var millisecond = 1000 * 60 * 60 * 24;

        //下月的第一天

        var nextMonthDayOne = new Date(currentYear, currentMonth, 1);

        //求出上月的最后一天

        var lastDay = new Date(nextMonthDayOne.getTime() - millisecond);

        //添加至数组中返回

        startStop.push(firstDay);

        startStop.push(lastDay);

        //返回

        return startStop;

    };

    /**

    * 得到本季度开始的月份

    * @param month 需要计算的月份

    ***/

    this.getQuarterSeasonStartMonth = function (month) {

        var quarterMonthStart = 0;

        var spring = 0; //春

        var summer = 3; //夏

        var fall = 6;   //秋

        var winter = 9; //冬

        //月份从0-11

        if (month < 3) {

            return spring;

        }

        if (month < 6) {

            return summer;

        }

        if (month < 9) {

            return fall;

        }

        return winter;

    };

    /**

    * 获得该月的天数

    * @param year年份

    * @param month月份

    * */

    this.getMonthDays = function (year, month) {

        //本月第一天 1-31

        var relativeDate = new Date(year, month, 1);

        //获得当前月份0-11

        var relativeMonth = relativeDate.getMonth();

        //获得当前年份4位年

        var relativeYear = relativeDate.getFullYear();

        //当为12月的时候年份需要加1

        //月份需要更新为0 也就是下一年的第一个月

        if (relativeMonth == 11) {

            relativeYear++;

            relativeMonth = 0;

        } else {

            //否则只是月份增加,以便求的下一月的第一天

            relativeMonth++;

        }

        //一天的毫秒数

        var millisecond = 1000 * 60 * 60 * 24;

        //下月的第一天

        var nextMonthDayOne = new Date(relativeYear, relativeMonth, 1);

        //返回得到上月的最后一天,也就是本月总天数

        return new Date(nextMonthDayOne.getTime() - millisecond).getDate();

    };

    /**

    * 获得本季度的起止日期

    */

    this.getCurrentSeason = function () {

        //起止日期数组

        var startStop = new Array();

        //获取当前时间

        var currentDate = this.getCurrentDate();

        //获得当前月份0-11

        var currentMonth = currentDate.getMonth();

        //获得当前年份4位年

        var currentYear = currentDate.getFullYear();

        //获得本季度开始月份

        var quarterSeasonStartMonth = this.getQuarterSeasonStartMonth(currentMonth);

        //获得本季度结束月份

        var quarterSeasonEndMonth = quarterSeasonStartMonth + 2;

        //获得本季度开始的日期

        var quarterSeasonStartDate = new Date(currentYear, quarterSeasonStartMonth, 1);

        //获得本季度结束的日期

        var quarterSeasonEndDate = new Date(currentYear, quarterSeasonEndMonth, this.getMonthDays(currentYear, quarterSeasonEndMonth));

        //加入数组返回

        startStop.push(quarterSeasonStartDate);

        startStop.push(quarterSeasonEndDate);

        //返回

        return startStop;

    };

    /***

    * 得到本年的起止日期

    *

    */

    this.getCurrentYear = function () {

        //起止日期数组

        var startStop = new Array();

        //获取当前时间

        var currentDate = this.getCurrentDate();

        //获得当前年份4位年

        var currentYear = currentDate.getFullYear();

        //本年第一天

        var currentYearFirstDate = new Date(currentYear, 0, 1);

        //本年最后一天

        var currentYearLastDate = new Date(currentYear, 11, 31);

        //添加至数组

        startStop.push(currentYearFirstDate);

        startStop.push(currentYearLastDate);

        //返回

        return startStop;

    };

    /**

    * 返回上一个月的第一天Date类型

    * @param year 年

    * @param month 月

    **/

    this.getPriorMonthFirstDay = function (year, month) {

        //年份为0代表,是本年的第一月,所以不能减

        if (month == 0) {

            month = 11; //月份为上年的最后月份

            year--; //年份减1

            return new Date(year, month, 1);

        }

        //否则,只减去月份

        month--;

        return new Date(year, month, 1);;

    };

    /**

    * 获得上一月的起止日期

    * ***/

    this.getPreviousMonth = function () {

        //起止日期数组

        var startStop = new Array();

        //获取当前时间

        var currentDate = this.getCurrentDate();

        //获得当前月份0-11

        var currentMonth = currentDate.getMonth();

        //获得当前年份4位年

        var currentYear = currentDate.getFullYear();

        //获得上一个月的第一天

        var priorMonthFirstDay = this.getPriorMonthFirstDay(currentYear, currentMonth);

        //获得上一月的最后一天

        var priorMonthLastDay = new Date(priorMonthFirstDay.getFullYear(), priorMonthFirstDay.getMonth(), this.getMonthDays(priorMonthFirstDay.getFullYear(), priorMonthFirstDay.getMonth()));

        //添加至数组

        startStop.push(priorMonthFirstDay);

        startStop.push(priorMonthLastDay);

        //返回

        return startStop;

    };

    /**

    * 获得上一周的起止日期

    * **/

    this.getPreviousWeek = function () {

        //起止日期数组

        var startStop = new Array();

        //获取当前时间

        var currentDate = this.getCurrentDate();

        //返回date是一周中的某一天

        var week = currentDate.getDay();

        //返回date是一个月中的某一天

        var month = currentDate.getDate();

        //一天的毫秒数

        var millisecond = 1000 * 60 * 60 * 24;

        //减去的天数

        var minusDay = week != 0 ? week - 1 : 6;

        //获得当前周的第一天

        var currentWeekDayOne = new Date(currentDate.getTime() - (millisecond * minusDay));

        //上周最后一天即本周开始的前一天

        var priorWeekLastDay = new Date(currentWeekDayOne.getTime() - millisecond);

        //上周的第一天

        var priorWeekFirstDay = new Date(priorWeekLastDay.getTime() - (millisecond * 6));

        //添加至数组

        startStop.push(priorWeekFirstDay);

        startStop.push(priorWeekLastDay);

        return startStop;

    };

    /**

    * 得到上季度的起始日期

    * year 这个年应该是运算后得到的当前本季度的年份

    * month 这个应该是运算后得到的当前季度的开始月份

    * */

    this.getPriorSeasonFirstDay = function (year, month) {

        var quarterMonthStart = 0;

        var spring = 0; //春

        var summer = 3; //夏

        var fall = 6;   //秋

        var winter = 9; //冬

        //月份从0-11

        switch (month) {//季度的其实月份

            case spring:

                //如果是第一季度则应该到去年的冬季

                year--;

                month = winter;

                break;

            case summer:

                month = spring;

                break;

            case fall:

                month = summer;

                break;

            case winter:

                month = fall;

                break;

        };

        return new Date(year, month, 1);

    };

    /**

    * 得到上季度的起止日期

    * **/

    this.getPreviousSeason = function () {

        //起止日期数组

        var startStop = new Array();

        //获取当前时间

        var currentDate = this.getCurrentDate();

        //获得当前月份0-11

        var currentMonth = currentDate.getMonth();

        //获得当前年份4位年

        var currentYear = currentDate.getFullYear();

        //上季度的第一天

        var priorSeasonFirstDay = this.getPriorSeasonFirstDay(currentYear, currentMonth);

        //上季度的最后一天

        var priorSeasonLastDay = new Date(priorSeasonFirstDay.getFullYear(), priorSeasonFirstDay.getMonth() + 2, this.getMonthDays(priorSeasonFirstDay.getFullYear(), priorSeasonFirstDay.getMonth() + 2));

        //添加至数组

        startStop.push(priorSeasonFirstDay);

        startStop.push(priorSeasonLastDay);

        return startStop;

    };

    /**

    * 得到去年的起止日期

    * **/

    this.getPreviousYear = function () {

        //起止日期数组

        var startStop = new Array();

        //获取当前时间

        var currentDate = this.getCurrentDate();

        //获得当前年份4位年

        var currentYear = currentDate.getFullYear();

        currentYear--;

        var priorYearFirstDay = new Date(currentYear, 0, 1);

        var priorYearLastDay = new Date(currentYear, 11, 1);

        //添加至数组

        startStop.push(priorYearFirstDay);

        startStop.push(priorYearLastDay);

        return startStop;

    };

    return this;

})();

/*

 * 使用:

case "本月":

    $("#startDate").val(dateRangeUtil.getCurrentMonth()[0].Format("yyyy-MM-dd"));

    $("#endDate").val(dateRangeUtil.getCurrentMonth()[1].Format("yyyy-MM-dd"));

    break;

 *

 */

<script type="text/javascript">

function showdate(n)

{

var uom = new Date(new Date()-0+n*86400000);

uom = uom.getFullYear() + "-" + (uom.getMonth()+1) + "-" + uom.getDate();

return uom;

}

window.alert("今天是："+showdate(0));

window.alert("昨天是："+showdate(-1));

window.alert("明天是："+showdate(1));

window.alert("10天前是："+showdate(-10));

window.alert("5天后是："+showdate(5));

</script>