年月日三级下拉菜单
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>无标题文档</title>
<script language="javascript" >
function YearMonthDay(){
fo=document.form1;
foday=fo.day1;
MonHead=[31,28,31,30,31,30,31,31,30,31,30,31];
//add options for year
y=new Date().getFullYear();
for(i=(y-80);i<=y;i++)
fo.year1.options.add(new Option(i,i));
//fo.year1.options.value=y;//current year
//add options for month
m=new Date().getMonth();
for(i=1;i<=12;i++)
fo.month1.options.add(new Option(i,i));
//fo.month1.options.value=m+1;//current month
//add options for day
d=new Date().getDate();
n=MonHead[m];
if(m==1&&IsRunYear(yearValue))
n++;
day(n);
//fo.day1.options.value=d;//curren day
}
//onchange of year
function yy(str){
monthValue=fo.month1.options[fo.month1.selectedIndex].value;
if(monthValue==""){
var foday=document.form1.day1;
optionClear(foday);
return;
}
var n=MonHead[monthValue-1];
if(monthValue==2&&IsRunYear(str)) n++;
day(n);
}
//onchange of month
function mm(ab){
yearValue=fo.year1.options[fo.year1.selectedIndex].value;
if(yearValue==""){
optionClear(foday);
return;
}
var n=MonHead[ab-1];
if(ab==2&&IsRunYear(yearValue)) n++;
day(n);
}
function day(ab){
optionClear(foday);
for(var i=1;i<=ab;i++)
foday.options.add(new Option(i,i));
}
function optionClear(ab){
for(var i=ab.options.length;i>0;i--)
ab.remove(i);
}
function IsRunYear(year){
return(0==year%4&&(year%100!=0 || year%400==0));
}
</script>
</head>
<body onload="YearMonthDay()">
<form name="form1" >
<select name="year1" id="year1" onchange="yy(this.value)"><option value="" selected>选择</option>
</select>
年
<select name="month1" id="month1" onchange="mm(this.value)"><option value="" selected>选择</option>
</select>
月
<select name="day1" id="day1"><option value="" selected>选择</option>
</select>
日
</form>
</body>
</html>
