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>