現(xiàn)在世界通用的公歷（陽(yáng)歷）也經(jīng)過(guò)一個(gè)長(zhǎng)期演變的過(guò)程。我
們先看，公歷每個(gè)月的日數(shù)是固定的："七前單大，八后雙大"。也
就是說(shuō)，一、三、五、七、八、十、臘月（十二月）是31天，四、
六、九、十一月是30天，只有二月，平年28天，閏年29天。
代碼 %@ Page Language="C#" AutoEventWireup="true" CodeBehind="WebForm1.aspx.cs" Inherits="WebApplication1.WebForm1" %
!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"
html xmlns="w3.org/1999/xhtml"
head runat="server"
title /title
/head
body
form id="form1" runat="server"
div
select name=YYYY id="YYYY" onchange="YYYYMM(this.value)"
option value="" 選擇 年 /option
/select
select name=MM id="MM" onchange="MMDD(this.value)"
option value="" 選擇 月 /option
/select
select name=DD id="DD"
option value="" 選擇 日 /option
/select
/div
asp:HiddenField ID="hfValue" runat="server" /
asp:Button ID="btnSave" runat="server" Text="保存" onclick="btnSave_Click" /
/form
/body
/html
script language="Javascript"
!--
function getValue() {
var year = document.getElementById("YYYY").options[document.getElementById("YYYY").selectedIndex].value;
var month = document.getElementById("MM").options[document.getElementById("MM").selectedIndex].value;
var day = document.getElementById("DD").options[document.getElementById("DD").selectedIndex].value;
document.getElementById("hfValue").value = year+"-"+month+"-"+day;
}
window.onload=function() {
strYYYY = document.form1.YYYY.outerHTML;
strMM = document.form1.MM.outerHTML;
strDD = document.form1.DD.outerHTML;
MonHead = [31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31];
//先給年下拉框賦內(nèi)容
var y = new Date().getFullYear();
var str = strYYYY.substring(0, strYYYY.length - 9);
for (var i = (y - 80); i (y + 2); i++) //以今年為準(zhǔn)，前30年，后30年
{
str += " option value='" + i + "' " + i + " 年" + " /option \r\n";
}
document.form1.YYYY.outerHTML = str + " /select ";
//賦月份的下拉框
var str = strMM.substring(0, strMM.length - 9);
for (var i = 1; i 13; i++) {
str += " option value='" + i + "' " + i + " 月" + " /option \r\n";
}
document.form1.MM.outerHTML = str + " /select ";
document.form1.YYYY.value = y;
document.form1.MM.value = new Date().getMonth() + 1;
var n = MonHead[new Date().getMonth()];
if (new Date().getMonth() == 1 IsPinYear(YYYYvalue)) n++;
writeDay(n); //賦日期下拉框
document.form1.DD.value = new Date().getDate();
}
function YYYYMM(str) //年發(fā)生變化時(shí)日期發(fā)生變化(主要是判斷閏平年)
{
var MMvalue = document.form1.MM.options[document.form1.MM.selectedIndex].value;
if (MMvalue == "") {
DD.outerHTML = strDD;
return;
}
var n = MonHead[MMvalue - 1];
if (MMvalue == 2 IsPinYear(str)) n++;
writeDay(n)
}
function MMDD(str) //月發(fā)生變化時(shí)日期聯(lián)動(dòng)
{
var YYYYvalue = document.form1.YYYY.options[document.form1.YYYY.selectedIndex].value;
if (str == "") {
DD.outerHTML = strDD;
return;
}
var n = MonHead[str - 1];
if (str == 2 IsPinYear(YYYYvalue)) n++;
writeDay(n)
}
function writeDay(n) //據(jù)條件寫(xiě)日期的下拉框
{
var s = strDD.substring(0, strDD.length - 9);
for (var i = 1; i (n + 1); i++) s += " option value='" + i + "' " + i + " 日" +
" /option \r\n";
document.form1.DD.outerHTML = s + " /select ";
}
function IsPinYear(year) //判斷是否閏平年
{
return (0 == year % 4 (year % 100 != 0 || year % 400 == 0))
}
//--
/script
