var now = new Date(); //當前日期
        var nowDayOfWeek = now.getDay(); //今天本週的第幾天
        var nowDay = now.getDate(); //當前日
        var nowMonth = now.getMonth(); //當前月
        var nowYear = now.getFullYear(); //當前年
  
        //獲得某月的天數
        function getMonthDays(myMonth){
            var monthStartDate = new Date(nowYear, myMonth, 1);
            var monthEndDate = new Date(nowYear, myMonth + 1, 1);
            var   days   =   (monthEndDate   -   monthStartDate)/(1000   *   60   *   60   *   24);
            return   days;
        }
  //獲得本週的開端日期
        function getWeekStartDate() {
            var weekStartDate = new Date(nowYear, nowMonth, nowDay - nowDayOfWeek + 1);
            return formatDate(weekStartDate);
        }

        //獲得本週的停止日期
        function getWeekEndDate() {
            var weekEndDate = new Date(nowYear, nowMonth, nowDay + (7 - nowDayOfWeek));
            return formatDate(weekEndDate);
        }

        //獲得本月的開端日期
        function getMonthStartDate(){
            var monthStartDate = new Date(nowYear, nowMonth, 1);
            return formatDate(monthStartDate);
        }

        //獲得本月的停止日期
        function getMonthEndDate(){
            var monthEndDate = new Date(nowYear, nowMonth, getMonthDays(nowMonth));
            return formatDate(monthEndDate);
        }
  //獲取本年的開始日期
  function getYearStartDate(){
   var monthStartDate = new Date(nowYear, 0, 1);
            return formatDate(monthStartDate);
  }
  //獲得某年某月的天數
        function getMonthDaysNew(year,month){
            var monthStartDate = new Date(year, month, 1);
            var monthEndDate = new Date(year,month + 1, 1);
            var   days   =   (monthEndDate   -   monthStartDate)/(1000   *   60   *   60   *   24);
            return   days;
        }
  //獲取某一天
  function getDateNew(year,month,newDay) {
            var weekStartDate = new Date(year, month, newDay);
            return formatDate(weekStartDate);
        }
  //獲取周的開始日期
  function getWeekStartDateNew(year,month,newDay,newDayOfWeek) {
            var weekStartDate = new Date(year, month, newDay - newDayOfWeek + 1);
            return formatDate(weekStartDate);
        }
  //獲得周的停止日期
        function getWeekEndDateNew(year,month,newDay,newDayOfWeek) {
            var weekEndDate = new Date(year, month, newDay + (7 - newDayOfWeek));
            return formatDate(weekEndDate);
        }
  //獲得月的開端日期
        function getMonthStartDateNew(year,month,newDay,newDayOfWeek){
            var monthStartDate = new Date(year, month, 1);
            return formatDate(monthStartDate);
        }
   //獲得月的停止日期
        function getMonthEndDateNew(year,month,newDay,newDayOfWeek){
            var monthEndDate = new Date(year, month, getMonthDaysNew(year,month));
            return formatDate(monthEndDate);
        }
  //獲取年的開始日期
  function getYearStartDateNew(year,month,newDay,newDayOfWeek){
   var monthStartDate = new Date(year, 0, 1);
            return formatDate(monthStartDate);
  }
  //獲取年的結束日期
  function getYearEndDateNew(year,month,newDay,newDayOfWeek){
   var monthStartDate = new Date(year, 11, 31);
            return formatDate(monthStartDate);
  }