<script language=javascript>
//今天
function showToDay()
{
var Nowdate=new Date();
M=Number(Nowdate.getMonth())+1
return Nowdate.getYear()+"-"+M+"-"+Nowdate.getDate();
}

//本周第一天
function showWeekFirstDay()
{
var Nowdate=new Date();
var WeekFirstDay=new Date(Nowdate-(Nowdate.getDay()-1)*86400000);
return WeekFirstDay;
}
//本周最后一天
function showWeekLastDay()
{
var Nowdate=new Date();
var WeekFirstDay=new Date(Nowdate-(Nowdate.getDay()-1)*86400000);
var WeekLastDay=new Date((WeekFirstDay/1000+6*86400)*1000);
return WeekLastDay;
}

//本月第一天
function showMonthFirstDay()
{
var Nowdate=new Date();
var MonthFirstDay=new Date(Nowdate.getYear(),Nowdate.getMonth(),1);
return MonthFirstDay;
}
//本月最后一天
function showMonthLastDay()
{
var Nowdate=new Date();
var MonthNextFirstDay=new Date(Nowdate.getYear(),Nowdate.getMonth()+1,1);
var MonthLastDay=new Date(MonthNextFirstDay-86400000);
return MonthLastDay;
}
//上月第一天
function showPreviousFirstDay()
{
 var MonthFirstDay=showMonthFirstDay()
 return new Date(MonthFirstDay.getYear(),MonthFirstDay.getMonth()-1,1)
}
//上月最后一天
function showPreviousLastDay()
{
 var MonthFirstDay=showMonthFirstDay();
 return new Date(MonthFirstDay-86400000);
}
//上周第一天
function showPreviousFirstWeekDay()
{
 var WeekFirstDay=showWeekFirstDay()
 return new Date(WeekFirstDay-86400000*7)
}
//上周最后一天
function showPreviousLastWeekDay()
{
 var WeekFirstDay=showWeekFirstDay()
 return new Date(WeekFirstDay-86400000)
}
//上一天
function showPreviousDay()
{
 var MonthFirstDay=new Date();
 return new Date(MonthFirstDay-86400000);
}
//下一天
function showNextDay()
{
 var MonthFirstDay=new Date();
 return new Date((MonthFirstDay/1000+86400)*1000);
}
//下周第一天
function showNextFirstWeekDay()
{
 var MonthFirstDay=showWeekLastDay()
 return new Date((MonthFirstDay/1000+86400)*1000)
}
//下周最后一天
function showNextLastWeekDay()
{
 var MonthFirstDay=showWeekLastDay()
 return new Date((MonthFirstDay/1000+7*86400)*1000)
}
//下月第一天
function showNextFirstDay()
{
 var MonthFirstDay=showMonthFirstDay()
 return new Date(MonthFirstDay.getYear(),MonthFirstDay.getMonth()+1,1)
}
//下月最后一天
function showNextLastDay()
{
 var MonthFirstDay=showMonthFirstDay()
 return new Date(new Date(MonthFirstDay.getYear(),MonthFirstDay.getMonth()+2,1)-86400000)
}
function Date.prototype.toString(){
return this.getFullYear()+"-"+(this.getMonth()+1)+"-"+this.getDate();
}
function setDate(num){
if(num==1){
 document.all.dateDate.value=showMonthFirstDay();
 document.all.dateDate2.value=showMonthLastDay();
 }
if(num==2){
 document.all.dateDate.value=showWeekFirstDay();
 document.all.dateDate2.value=showWeekLastDay();
 }
if(num==3){
 document.all.dateDate.value=showToDay();
 document.all.dateDate2.value=showToDay();
 }
if(num==4){
 document.all.dateDate.value=showPreviousFirstDay();
 document.all.dateDate2.value=showPreviousLastDay();
 }
if(num==5){
 document.all.dateDate.value=showNextFirstDay();
 document.all.dateDate2.value=showNextLastDay();
 }
if(num==6){
 document.all.dateDate.value=showPreviousFirstWeekDay();
 document.all.dateDate2.value=showPreviousLastWeekDay();
 }
if(num==7){
 document.all.dateDate.value=showNextFirstWeekDay();
 document.all.dateDate2.value=showNextLastWeekDay();
 }
if(num==8){
 document.all.dateDate.value=showPreviousDay();
 document.all.dateDate2.value=showPreviousDay();
 }
if(num==9){
 document.all.dateDate.value=showNextDay();
 document.all.dateDate2.value=showNextDay();
 }
}

</script>
<input name=dateDate type=text>-><input name=dateDate2 type=text>
&nbsp;<input name=haha type=button value="上一月" onclick=setDate(4)>&nbsp;
&nbsp;<input name=haha type=button value="本月" onclick=setDate(1)>&nbsp;
<input name=haha type=button value="下一月" onclick=setDate(5)>&nbsp;
<input name=haha type=button value="上一周" onclick=setDate(6)>&nbsp;
<input name=haha type=button value="本周" onclick=setDate(2)>&nbsp;
<input name=haha type=button value="下一周" onclick=setDate(7)>&nbsp;
<input name=haha type=button value="上一天" onclick=setDate(8)>&nbsp;
<input name=haha type=button value="今天" onclick=setDate(3)>&nbsp;
<input name=haha type=button value="下一天" onclick=setDate(9)>