JS 日期操作

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