js获得本周，本月，本季度的开始日期和结束日期

 1 <script>
 2 var now = new Date();                    //当前日期
 3 var nowDayOfWeek = now.getDay();         //今天本周的第几天
 4 var nowDay = now.getDate();              //当前日
 5 var nowMonth = now.getMonth();           //当前月
 6 var nowYear = now.getYear();             //当前年
 7 nowYear += (nowYear < 2000) ? 1900 : 0;  //
 8
 9 //格式化日期：yyyy-MM-dd
10 function formatDate(date) {
11     var myyear = date.getFullYear();
12     var mymonth = date.getMonth()+1;
13     var myweekday = date.getDate();
14
15     if(mymonth < 10){
16         mymonth = "0" + mymonth;
17     }
18     if(myweekday < 10){
19         myweekday = "0" + myweekday;
20     }
21     return (myyear+"-"+mymonth + "-" + myweekday);
22 }
23
24 //获得某月的天数
25 function getMonthDays(myMonth){
26     var monthStartDate = new Date(nowYear, myMonth, 1);
27     var monthEndDate = new Date(nowYear, myMonth + 1, 1);
28     var   days   =   (monthEndDate   -   monthStartDate)/(1000   *   60   *   60   *   24);
29     return   days;
30 }
31
32 //获得本季度的开始月份
33 function getQuarterStartMonth(){
34     var quarterStartMonth = 0;
35     if(nowMonth<3){
36        quarterStartMonth = 0;
37     }
38     if(2<nowMonth && nowMonth<6){
39        quarterStartMonth = 3;
40     }
41     if(5<nowMonth && nowMonth<9){
42        quarterStartMonth = 6;
43     }
44     if(nowMonth>8){
45        quarterStartMonth = 9;
46     }
47     return quarterStartMonth;
48 }
49
50 //获得本周的开始日期
51 function getWeekStartDate() {
52     var weekStartDate = new Date(nowYear, nowMonth, nowDay - nowDayOfWeek);
53     return formatDate(weekStartDate);
54 }
55
56 //获得本周的结束日期
57 function getWeekEndDate() {
58     var weekEndDate = new Date(nowYear, nowMonth, nowDay + (6 - nowDayOfWeek));
59     return formatDate(weekEndDate);
60 }
61
62 //获得本月的开始日期
63 function getMonthStartDate(){
64     var monthStartDate = new Date(nowYear, nowMonth, 1);
65     return formatDate(monthStartDate);
66 }
67
68 //获得本月的结束日期
69 function getMonthEndDate(){
70     var monthEndDate = new Date(nowYear, nowMonth, getMonthDays(nowMonth));
71     return formatDate(monthEndDate);
72 }
73
74 //获得本季度的开始日期
75 function getQuarterStartDate(){
76
77     var quarterStartDate = new Date(nowYear, getQuarterStartMonth(), 1);
78     return formatDate(quarterStartDate);
79 }
80
81 //或的本季度的结束日期
82 function getQuarterEndDate(){
83     var quarterEndMonth = getQuarterStartMonth() + 2;
84     var quarterStartDate = new Date(nowYear, quarterEndMonth, getMonthDays(quarterEndMonth));
85     return formatDate(quarterStartDate);
86 }
87
88 alert(getQuarterEndDate());
89 </script>