<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<html>
<head>
<title> New Document </title>
<meta name="Generator" content="EditPlus">
<meta name="Author" content="">
<meta name="Keywords" content="">
<meta name="Description" content="">
<script language="javascript">
function YYYYMMDDstart()
{
MonHead = [31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31];
//先给年下拉框赋内容
var y = new Date().getFullYear();
for (var i = (y-30); i < (y-10); i++) //以今年为准，显示前30年之后的20年
document.form1.YYYY.options.add(new Option(""+i+"", i));
//赋月份的下拉框
for (var i = 1; i < 13; i++)
document.form1.MM.options.add(new Option(""+i+"", i));
// document.form1.YYYY.value = y; //获取到当前年份
// document.form1.MM.value = new Date().getMonth() + 1; 获取到当前月份
var n = MonHead[new Date().getMonth()];
if (new Date().getMonth() ==1 && IsPinYear(YYYYvalue)) n++;
writeDay(n); //赋日期下拉框Author:meizz
// document.form1.DD.value = new Date().getDate(); 获取到当前日期
}
function YYYYDD(str) //年发生变化时日期发生变化(主要是判断闰平年)
{
var MMvalue = document.form1.MM.options[document.form1.MM.selectedIndex].value;
if (MMvalue == ""){ var e = document.form1.DD; optionsClear(e); return;}
var n = MonHead[MMvalue - 1];
if (MMvalue ==2 && IsPinYear(str)) n++;
writeDay(n)
}
function MMDD(str) //月发生变化时日期联动
{
var YYYYvalue = document.form1.YYYY.options[document.form1.YYYY.selectedIndex].value;
if (YYYYvalue == ""){ var e = document.form1.DD; optionsClear(e); return;}
var n = MonHead[str - 1];
if (str ==2 && IsPinYear(YYYYvalue)) n++;
writeDay(n)
}
function writeDay(n) //据条件写日期的下拉框
{
var e = document.form1.DD; optionsClear(e);
for (var i=1; i<(n+1); i++)
e.options.add(new Option(""+i+"", i));
}
function IsPinYear(year)//判断是否闰平年
{ return(0 == year%4 && (year%100 !=0 || year%400 == 0));}
function optionsClear(e)
{
for (var i=e.options.length; i>0; i--)
e.remove(i);
}
</script>
</head>
<body onload="YYYYMMDDstart()">
<form name="form1">
<select name="YYYY" onchange="YYYYDD(this.value)">
<option value="0">选择年</option>
</select>
<select name="MM" onchange="MMDD(this.value)">
<option value="0">选择月</option>
</select>
<select name="DD">
<option value="0">选择日</option>
</select>
</form>
</body>
</html>