关于用select选择确定月日

Question

<SELECT NAME="imonth" onchange="chgMth(this.value);">
<SCRIPT LANGUAGE="JavaScript">
<!--
for (var i=1;i<13;i++){
document.write("<option value="+i+">"+i+"</option>");
}
//-->
</SCRIPT>
</SELECT>
<SELECT NAME="iday"></SELECT>
<SCRIPT LANGUAGE="JavaScript">
<!--
chgMth(1);
function chgMth(im){
var tmp;
if (im==1 || im==3 || im==5 || im==7 || im==8 || im==10 || im==12) { tmp = 31; }
if (im==4 || im==6 || im==9 || im==11){ tmp = 30; }
if (im==2) { tmp = 28; }
document.all.iday.options.length=0;
for (var i=1;i<tmp+1;i++){
document.all.iday.options[document.all.iday.options.length] = new Option(i,i);
}
}
//-->
</SCRIPT>

Answer 1

秋水写的连动菜单（选择时间）<form>
<select id=year onchange=toDate()>
<script>for(i=1970;i<=2010;i++)document.write("<option>"+i+"</option>")</script>
</select>
<select id=month onchange=toDate()>
<script>for(i=1;i<=12;i++)document.write("<option>"+i+"</option>")</script>
</select>
<select id=day onchange=toDay()></select>
<input name=weekday>
</form>
<script>
var arr="日一二三四五六".split("")function toDate(){
with(document.all){
vYear=parseInt(year.options[year.selectedIndex].text)
vMonth=parseInt(month.options[month.selectedIndex].text)
day.length=0;
for(i=0;i<(new Date(vYear,vMonth,0)).getDate();i++){day.options[day.length++].value=day.length;day.options[day.length-1].text=day.length;}
}
toDay();
}function toDay(){
vDay=parseInt(document.all.day.options[document.all.day.selectedIndex].value)
document.all("weekday").value="星期"+arr[new Date(vYear,vMonth-1,vDay).getDay()]
}window.onload=toDate;
</script>