實作目标：
兩個日期，有下拉框：
<head>
//導入jquery位址
<script src="（jquery位址）" language="javascript" type="text/javascript"></script>
<script type="text/javascript">
//startyear發生變化
function changeyear(str,isstart)
{
var pre = "start";
if(isstart == false)
pre = "end";
}
var startmonth = $(pre + "month").value;
if(startmonth == "")
var e = $(pre + "month");
optionclear(e);
return;
var n = monhead[startmonth - 1];
if(startmonth == 2 && ispinyear($(pre + "year").value))
n++;
writeday(n,pre);
function changemonth(str,isstart)
var year = $(pre + "year").value;
if(year == "")
var e = $(pre + "day");
var n = monhead[str - 1];
if(str == 2 && ispinyear($(pre + "year")))
function datestart()
var defaultstarty = "2011";
var defaultstartm = "1";
var defaultstartd = "14";
var defaultendy = "2011";
var defaultendm = "2";
var defaultendd = "23";
monhead = [31,28,31,30,31,30,31,31,30,31,30,31];
var prestr = new array("start","end");
for(var j=0; j<2; j++)
var pre = prestr[j];
//start 年
var y = new date().getfullyear();
if(pre == "start")
//start初始選中前第10天
var i_index = 0;
for(var i=(y-10); i<=y; i++)
$(pre+"year").options.add(new option(""+i+"",i));
if(i == defaultstarty)
$(pre+"year").options[i_index].selected = true;
i_index++;
else
var i_index =0;
for(var i=(y-5); i<=y+5; i++)
if(i == defaultendy)
//start月
defaultm = (pre == "start" ? defaultstartm : defaultendm)
for(var i = 1; i < 13; i++)
$(pre + "month").options.add(new option(""+i+"",i));
if(i == defaultm)
$(pre + "month").options[i-1].selected = true;
//start日
var n = monhead[$(pre + "month").value];
if(new date().getmonth == 1 && ispinyear($(pre + "year").value))
defaultd = (pre == "start" ? defaultstartd : defaultendd)
$(pre + "day").options[defaultd-1].selected = true;
function writeday(n,pre)
for (var i=1; i<(n+1); i++)
e.options.add(new option(""+i+"",i));
function ispinyear(year)
return (0 == year%4 && (year%100 != 0 || year % 4 == 0));
function optionclear(e)
for(var i=e.options.length; i>=0; i--)
e.remove(i);
</script>
</head>
<body onload="datestart()">
<p name="selectdate">
從
<select id="startyear" name="startyear" onchange="changeyear(this.value,true)">
</select>
年
<select id="startmonth" name="startmonth" onchange="changemonth(this.value,true)">
月
<select id="startday" name="startday">
日
到
<select id="endyear" name="endyear" onchange="changeyear(this.value,false)">
<select id="endmonth" name="endmonth" onchange="changemonth(this.value,false)">
<select id="endday" name="endday">
</p>
</body>
參考了一些代碼，終于能實作了~~