js对时间操作函数

print?
自己写的：
/*
* 求某年某月的总天数
*/
function getDates(year, month) {
var now2 = new Date(year, month, 0); // 这是本月的最后一天
return now2.getDate();
}
/*
* 获取某年某月1号的星期序号
*/
function getFirstDay(year, month) {
var now = new Date(year, month - 1, 1);
var day = now.getDay();

if (day == 0)
return 7;
else {
return day;
}
}
/*
* 求某年某月星期的总数
*/
function getDays(year, month) {
if (getDates(year, month) - 28 +getFirstDay(year,month) >
return 6;
if (getDates(year, month) == 28
&& getFirstDay(year, month) == 1)
return 4;
else
return 5;
}

其他文章中转来的
1.<mce:script language=javascript><!-- 
    
2.//一天含 86,400,000 毫秒(24* 60 * 60*1000)     
3.   
4.//今天     
5.function showToDay()    
6.{    
7.var Nowdate=new Date();    
8.M=Number(Nowdate.getMonth())+1    
9.return Nowdate.getYear()+"-"+M+"-"+Nowdate.getDate();    
10.}    
11.   
12.//本周第一天     
13.function showWeekFirstDay()    
14.{    
15.var Nowdate=new Date();    
16.var WeekFirstDay=new Date(Nowdate-(Nowdate.getDay()-1)*86400000);    
17.return WeekFirstDay;    
18.}    
19.//本周最后一天     
20.function showWeekLastDay()    
21.{    
22.var Nowdate=new Date();    
23.var WeekFirstDay=new Date(Nowdate-(Nowdate.getDay()-1)*86400000);    
24.var WeekLastDay=new Date((WeekFirstDay/1000+6*86400)*1000);    
25.return WeekLastDay;    
26.}    
27.   
28.//本月第一天     
29.function showMonthFirstDay()    
30.{    
31.var Nowdate=new Date();    
32.var MonthFirstDay=new Date(Nowdate.getYear(),Nowdate.getMonth(),1);    
33.return MonthFirstDay;    
34.}    
35.//本月最后一天     
36.function showMonthLastDay()    
37.{    
38.var Nowdate=new Date();    
39.var MonthNextFirstDay=new Date(Nowdate.getYear(),Nowdate.getMonth    
40.   
41.()+1,1);    
42.var MonthLastDay=new Date(MonthNextFirstDay-86400000);    
43.return MonthLastDay;    
44.}    
45.//上月第一天     
46.function showPreviousFirstDay()    
47.{    
48.var MonthFirstDay=showMonthFirstDay()    
49.return new Date(MonthFirstDay.getYear(),MonthFirstDay.getMonth()-    
50.   
51.1,1)    
52.}    
53.//上月最后一天     
54.function showPreviousLastDay()    
55.{    
56.var MonthFirstDay=showMonthFirstDay();    
57.return new Date(MonthFirstDay-86400000);    
58.}    
59.//上周第一天     
60.function showPreviousFirstWeekDay()    
61.{    
62.var WeekFirstDay=showWeekFirstDay()    
63.return new Date(WeekFirstDay-86400000*7)    
64.}    
65.//上周最后一天     
66.function showPreviousLastWeekDay()    
67.{    
68.var WeekFirstDay=showWeekFirstDay()    
69.return new Date(WeekFirstDay-86400000)    
70.}    
71.//上一天     
72.function showPreviousDay()    
73.{    
74.var MonthFirstDay=new Date();    
75.return new Date(MonthFirstDay-86400000);    
76.}    
77.//下一天     
78.function showNextDay()    
79.{    
80.var MonthFirstDay=new Date();    
81.return new Date((MonthFirstDay/1000+86400)*1000);    
82.}    
83.//下周第一天     
84.function showNextFirstWeekDay()    
85.{    
86.var MonthFirstDay=showWeekLastDay()    
87.return new Date((MonthFirstDay/1000+86400)*1000)    
88.}    
89.//下周最后一天     
90.function showNextLastWeekDay()    
91.{    
92.var MonthFirstDay=showWeekLastDay()    
93.return new Date((MonthFirstDay/1000+7*86400)*1000)    
94.}    
95.//下月第一天     
96.function showNextFirstDay()    
97.{    
98.var MonthFirstDay=showMonthFirstDay()    
99.return new Date(MonthFirstDay.getYear(),MonthFirstDay.getMonth()    
100.   
101.+1,1)    
102.}    
103.//下月最后一天     
104.function showNextLastDay()    
105.{    
106.var MonthFirstDay=showMonthFirstDay()    
107.return new Date(new Date(MonthFirstDay.getYear    
108.   
109.(),MonthFirstDay.getMonth()+2,1)-86400000)    
110.}    
111.function Date.prototype.toString(){    
112.return this.getFullYear()+"-"+(this.getMonth()+1)+"-"+this.getDate    
113.   
114.();    
115.}    
116.function setDate(num){    
117.if(num==1){    
118.document.all.dateDate.value=showMonthFirstDay();    
119.document.all.dateDate2.value=showMonthLastDay();    
120.}    
121.if(num==2){    
122.document.all.dateDate.value=showWeekFirstDay();    
123.document.all.dateDate2.value=showWeekLastDay();    
124.}    
125.if(num==3){    
126.document.all.dateDate.value=showToDay();    
127.document.all.dateDate2.value=showToDay();    
128.}    
129.if(num==4){    
130.document.all.dateDate.value=showPreviousFirstDay();    
131.document.all.dateDate2.value=showPreviousLastDay();    
132.}    
133.if(num==5){    
134.document.all.dateDate.value=showNextFirstDay();    
135.document.all.dateDate2.value=showNextLastDay();    
136.}    
137.if(num==6){    
138.document.all.dateDate.value=showPreviousFirstWeekDay();    
139.document.all.dateDate2.value=showPreviousLastWeekDay();    
140.}    
141.if(num==7){    
142.document.all.dateDate.value=showNextFirstWeekDay();    
143.document.all.dateDate2.value=showNextLastWeekDay();    
144.}    
145.if(num==8){    
146.document.all.dateDate.value=showPreviousDay();    
147.document.all.dateDate2.value=showPreviousDay();    
148.}    
149.if(num==9){    
150.document.all.dateDate.value=showNextDay();    
151.document.all.dateDate2.value=showNextDay();    
152.}    
153.}    
154.   
155. 
// --></mce:script>     
156.<input name=dateDate type=text>-><input name=dateDate2 type=text>    
157. <input name=haha type=button value="上一月" onclick=setDate    
158.   
159.(4)>     
160. <input name=haha type=button value="本月" onclick=setDate(1)    
161.   
162.>     
163.<input name=haha type=button value="下一月" onclick=setDate(5)    
164.   
165.>     
166.<input name=haha type=button value="上一周" onclick=setDate(6)    
167.   
168.>     
169.<input name=haha type=button value="本周" onclick=setDate(2)>     
170.<input name=haha type=button value="下一周" onclick=setDate(7)    
171.   
172.>     
173.<input name=haha type=button value="上一天" onclick=setDate(8)    
174.   
175.>     
176.<input name=haha type=button value="今天" onclick=setDate(3)>     
177.<input name=haha type=button value="下一天" onclick=setDate(9)>