JS日期处理工具类

    <script>           var now = new Date();                    //当前日期           var nowDayOfWeek = now.getDay();         //今天本周的第几天           var nowDay = now.getDate();              //当前日           var nowMonth = now.getMonth();           //当前月           var nowYear = now.getYear();             //当前年           nowYear += (nowYear < 2000) ? 1900 : 0;  //                     //格式化日期：yyyy-MM-dd           function formatDate(date) {                var myyear = date.getFullYear();               var mymonth = date.getMonth()+1;               var myweekday = date.getDate();                               if(mymonth < 10){                   mymonth = "0" + mymonth;               }                if(myweekday < 10){                   myweekday = "0" + myweekday;               }               return (myyear+"-"+mymonth + "-" + myweekday);            }                      //获得某月的天数           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;            }                     //获得本季度的开始月份           function getQuarterStartMonth(){               var quarterStartMonth = 0;               if(nowMonth<3){                  quarterStartMonth = 0;               }               if(2<nowMonth && nowMonth<6){                  quarterStartMonth = 3;               }               if(5<nowMonth && nowMonth<9){                  quarterStartMonth = 6;               }               if(nowMonth>8){                  quarterStartMonth = 9;               }               return quarterStartMonth;           }                     //获得本周的开始日期           function getWeekStartDate() {                var weekStartDate = new Date(nowYear, nowMonth, nowDay - nowDayOfWeek);                return formatDate(weekStartDate);           }                      //获得本周的结束日期           function getWeekEndDate() {                var weekEndDate = new Date(nowYear, nowMonth, nowDay + (6 - nowDayOfWeek));                return formatDate(weekEndDate);           }                      //获得本月的开始日期           function getMonthStartDate(){               var monthStartDate = new Date(nowYear, nowMonth, 1);                return formatDate(monthStartDate);           }                     //获得本月的结束日期           function getMonthEndDate(){               var monthEndDate = new Date(nowYear, nowMonth, getMonthDays(nowMonth));                return formatDate(monthEndDate);           }                     //获得本季度的开始日期           function getQuarterStartDate(){                              var quarterStartDate = new Date(nowYear, getQuarterStartMonth(), 1);                return formatDate(quarterStartDate);           }                     //或的本季度的结束日期           function getQuarterEndDate(){               var quarterEndMonth = getQuarterStartMonth() + 2;               var quarterStartDate = new Date(nowYear, quarterEndMonth, getMonthDays(quarterEndMonth));                return formatDate(quarterStartDate);           }                     alert(getQuarterEndDate());           </script>