复制代码 代码如下:

<div>

<select name="YYYY" onchange="YYYYMM(this.value)">

<option value="">请选择 年</option>

</select>

<select name="MM" onchange="MMDD(this.value)">

<option value="">选择 月</option>

</select>

<select name="DD">

<option value="">选择 日</option>

</select>

</div>

<script language="JavaScript">

function window.onload() {

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];

//先给年下拉框赋内容

var y = new Date().getFullYear();

var str = strYYYY.substring(0, strYYYY.length - 9);

for (var i = (y - 30); i < (y + 30); i++) //以今年为准，前30年，后30年

{

str += "<option value='" + i + "'> " + i + " 年" + "</option>rn";

}

document.form1.YYYY.outerHTML = str + "</select>";

//赋月份的下拉框

var str = strMM.substring(0, strMM.length - 9);

for (var i = 1; i < 13; i++) {

str += "<option value='" + i + "'> " + i + " 月" + "</option>rn";

}

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); //赋日期下拉框

document.form1.DD.value = new Date().getDate();

}

function YYYYMM(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 == "") { DD.outerHTML = strDD; 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 (str == "") { DD.outerHTML = strDD; 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 s = strDD.substring(0, strDD.length - 9);

for (var i = 1; i < (n + 1); i++)

s += "<option value='" + i + "'> " + i + " 日" + "</option>rn";

document.form1.DD.outerHTML = s + "</select>";

}

function IsPinYear(year)//判断是否闰平年

{

return (0 == year % 4 && (year % 100 != 0 || year % 400 == 0))

}