日期选择控件ShowCalendar.js（可直接复制使用）

// 日期选择
// By Ziyue(http://www.web-v.com/)
// 使用方法：
// <script type="text/javascript" src="${pageContext.request.contextPath }/js/ShowCalendar.js"></script>
// <input name="birthday" type="text" id="birthday" title="点击选择" onClick="showCalendar(this.id)">

var today;
document.writeln("<div id='Calendar' style='position:absolute; z-index:1; visibility: hidden; filter:\"progid:DXImageTransform.Microsoft.Shadow(direction=135,color=#999999,strength=3)\"'></div>");

function getDays(month, year)
{
var daysInMonth = new Array(31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31);
//下面的这段代码是判断当前是否是闰年的
if (1 == month)
return ((0 == year % 4) && (0 != (year % 100))) || (0 == year % 400) ? 29 : 28;
else
return daysInMonth[month];
}

function getToday()
{
//得到今天的年,月,日
this.now = new Date();
this.year = this.now.getFullYear();
this.month = this.now.getMonth();
this.day = this.now.getDate();
}

function getStringDay(str)
{
//得到输入框的年,月,日
var str=str.split("-")

this.now = new Date(parseFloat(str[0]),parseFloat(str[1])-1,parseFloat(str[2]));
this.year = this.now.getFullYear();
this.month = this.now.getMonth();
this.day = this.now.getDate();
}

function newCalendar() {
var parseYear = parseInt(document.all.Year.options[document.all.Year.selectedIndex].value);
var newCal = new Date(parseYear, document.all.Month.selectedIndex, 1);
var day = -1;
var startDay = newCal.getDay();
var daily = 0;

if ((today.year == newCal.getFullYear()) &&(today.month == newCal.getMonth()))
day = today.day;

var tableCal = document.all.calendar;
var intDaysInMonth =getDays(newCal.getMonth(), newCal.getFullYear());

for (var intWeek = 1; intWeek < tableCal.rows.length;intWeek++)
for (var intDay = 0;intDay < tableCal.rows[intWeek].cells.length;intDay++)
{
var cell = tableCal.rows[intWeek].cells[intDay];
if ((intDay == startDay) && (0 == daily))
daily = 1;

if(day==daily) //今天，调用今天的Class
{
cell.style.background='#6699CC';
cell.style.color='#FFFFFF';
//cell.style.fontWeight='bold';
}
else if(intDay==6) //周六
cell.style.color='green';
else if (intDay==0) //周日
cell.style.color='red';

if ((daily > 0) && (daily <= intDaysInMonth))
{
cell.innerText = daily;
daily++;
}
else
cell.innerText = "";
}
}

function GetDate(InputBox)
{
var sDate;
//这段代码处理鼠标点击的情况
if (event.srcElement.tagName == "TD")
if (event.srcElement.innerText != "")
{
sDate = document.all.Year.value + "-" + document.all.Month.value + "-" + event.srcElement.innerText;
eval("document.all."+InputBox).value=sDate;
HiddenCalendar();
}
}

function HiddenCalendar()
{
//关闭选择窗口
document.all.Calendar.style.visibility='hidden';
}

function showCalendar(InputBox)
{
var months = new Array("一月", "二月", "三月", "四月", "五月", "六月", "七月", "八月", "九月", "十月", "十一月", "十二月");
var days = new Array("日","一", "二", "三", "四", "五", "六");

var x,y,intLoop,intWeeks,intDays;
var DivContent;
var year,month,day;
var o=eval("document.all."+InputBox);
var thisyear; //真正的今年年份

thisyear=new getToday();
thisyear=thisyear.year;

today = o.value;
if(isDate(today))
today = new getStringDay(today);
else
today = new getToday();

//显示的位置
x=o.offsetLeft;
y=o.offsetTop;
while(o=o.offsetParent)
{
x+=o.offsetLeft;
y+=o.offsetTop;
}
document.all.Calendar.style.left=x+2;
document.all.Calendar.style.top=y+20;
document.all.Calendar.style.visibility="visible";

//下面开始输出日历表格(border-color:#9DBAF7)
DivContent="<table border='0' cellspacing='0' style='border:1px solid #0066FF; background-color:#EDF2FC'>";
DivContent+="<tr>";
DivContent+="<td style='border-bottom:1px solid #0066FF; background-color:#C7D8FA'>";

//年
DivContent+="<select name='Year' id='Year' onChange='newCalendar()' style='font-family:Verdana; font-size:12px'>";
for (intLoop = thisyear - 35; intLoop < (thisyear + 2); intLoop++)
DivContent+="<option value= " + intLoop + " " + (today.year == intLoop ? "Selected" : "") + ">" + intLoop + "</option>";
DivContent+="</select>";

//月
DivContent+="<select name='Month' id='Month' onChange='newCalendar()' style='font-family:Verdana; font-size:12px'>";
for (intLoop = 0; intLoop < months.length; intLoop++)
DivContent+="<option value= " + (intLoop + 1) + " " + (today.month == intLoop ? "Selected" : "") + ">" + months[intLoop] + "</option>";
DivContent+="</select>";

DivContent+="</td>";

DivContent+="<td style='border-bottom:1px solid #0066FF; background-color:#C7D8FA; font-weight:bold; font-family:Wingdings 2,Wingdings,Webdings; font-size:16px; padding-top:2px; color:#4477FF; cursor:hand' align='center' title='关闭' onClick='javascript:HiddenCalendar()'>S</td>";
DivContent+="</tr>";

DivContent+="<tr><td align='center' colspan='2'>";
DivContent+="<table id='calendar' border='0' width='100%'>";

//星期
DivContent+="<tr>";
for (intLoop = 0; intLoop < days.length; intLoop++)
DivContent+="<td align='center' style='font-size:12px'>" + days[intLoop] + "</td>";
DivContent+="</tr>";

//天
for (intWeeks = 0; intWeeks < 6; intWeeks++)
{
DivContent+="<tr>";
for (intDays = 0; intDays < days.length; intDays++)
DivContent+="<td onClick='GetDate(\"" + InputBox + "\")' style='cursor:hand; border-right:1px solid #BBBBBB; border-bottom:1px solid #BBBBBB; color:#215DC6; font-family:Verdana; font-size:12px' align='center'></td>";
DivContent+="</tr>";
}
DivContent+="</table></td></tr></table>";

document.all.Calendar.innerHTML=DivContent;
newCalendar();
}

function isDate(dateStr)
{
var datePat = /^(\d{4})(\-)(\d{1,2})(\-)(\d{1,2})$/;
var matchArray = dateStr.match(datePat);
if (matchArray == null) return false;
var month = matchArray[3];
var day = matchArray[5];
var year = matchArray[1];
if (month < 1 || month > 12) return false;
if (day < 1 || day > 31) return false;
if ((month==4 || month==6 || month==9 || month==11) && day==31) return false;
if (month == 2)
{
var isleap = (year % 4 == 0 && (year % 100 != 0 || year % 400 == 0));
if (day > 29 || (day==29 && !isleap)) return false;
}
return true;
}