/*
<form id="form1" name="form1">
<select name="YYYY" onchange="YYYYDD(this.value)">
<option value="" selected>请选择 年</option>
</select>
<select name="MM" onchange="MMDD(this.value)">
<option value="" selected>选择 月</option>
</select>
<select name="DD" onchange="SELDD(this.value)">
<option value="" selected>选择 日</option>
</select>
</form>
*/
var yyyyid="";
var mmid="";
var ddid="";
var yyyyV="";
var mmV="";
var ddV="";

function YYYYMMDDstart(selyyyyid,selmmid,selddid,yyyyValue,mmValue,ddValue)
{
	yyyyid=selyyyyid;
	mmid=selmmid;
	ddid=selddid;
    ddV=ddValue;
	MonHead = [31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31];

	var y   = new Date().getFullYear();
	for (var j=0,i = (y-100); i < y;j++, i++) 
		document.getElementById(yyyyid).options.add(new Option(" "+ i +" 年", i));
	for (var i = 1; i < 13; i++)
		document.getElementById(mmid).options.add(new Option(" " + i + " 月", i));

	if (yyyyValue!="")
	    document.getElementById(yyyyid).value = yyyyValue;
	if (mmValue!="")
	    document.getElementById(mmid).value = mmValue;
	var n = 31;
	if (mmValue!="")
	{
	    n = MonHead[mmValue - 1];
	    if (mmValue ==2 && IsPinYear(yyyyValue))
			n++;
	}
	
	writeDay(n);
	//DD.value = new Date().getDate();
	if (ddValue!="")
	    document.getElementById(ddid).value = ddValue;
}
function YYYYDD(str)
{
	var MMvalue = document.getElementById(mmid).options[document.getElementById(mmid).selectedIndex].value;
	if (MMvalue == "" || str=="")
	{
	    //var e = document.getElementById(ddid); optionsClear(e); 
	    return;
	}
	var n = MonHead[MMvalue - 1];
	if (MMvalue ==2 && IsPinYear(str))
	    n++;
	writeDay(n);
	if (ddV!="")
        document.getElementById(ddid).value = ddV;
}
function MMDD(str)
{
	var YYYYvalue = document.getElementById(yyyyid).options[document.getElementById(yyyyid).selectedIndex].value;
	if (YYYYvalue == "")
	{
	    //var e = document.getElementById(ddid); optionsClear(e); 
	    return;
	}
	var n = MonHead[str - 1];
	if (str ==2 && IsPinYear(YYYYvalue)) n++;
		writeDay(n);
	if (ddV!="")
        document.getElementById(ddid).value = ddV;
}
function SELDD(str)
{
    ddV=str;
}
function writeDay(n)
{
	var e = document.getElementById(ddid); optionsClear(e);
	for (var i=1; i<(n+1); i++)
		e.options.add(new Option(" "+ i + " 日", i));
}
function IsPinYear(year)
{  
	return(0 == year%4 && (year%100 !=0 || year%400 == 0));
}
function optionsClear(e)
{
	e.options.length = 1;
}
//YYYYMMDDstart("YYYY","MM","DD",1981,7,12);