menuItem=[];
menuValu=[];
window.onload = function setYears(){
	myD = new Date();
	myYear = myD.getYear();
	myYear = (myYear < 2000) ? myYear+1900 : myYear;
	myDate    = myD.getDate();
	
	var yearchk = "1";
	for(cnt=0; cnt<6; cnt++){
		myMonth = myD.getMonth() + cnt + 1;
		if(myMonth > 12){
			myMonth = myMonth - 12;
			if(yearchk == "1"){
				myYear = myYear + 1;
				yearchk = "2";
			}
		}
		
		menuItem = myYear + "年" + myMonth + "月";
		
		wkMonth = myMonth + "";
		if(wkMonth.length == 1){
			wkMonth = "0" + wkMonth;
		}
		menuValu = (myYear + "") + wkMonth;

		document.form.k_ym.options[cnt] = new Option(menuItem,menuValu);
	}
	myYear = (myYear < 2000) ? myYear+1900 : myYear;
	myMonth = myD.getMonth() + 1;

	var lastday = monthday(myYear,myMonth);
	
	var intidx = 0;
	for (cnt = 1;cnt <= lastday;cnt++) {
		document.form.k_d.options[intidx] = new Option(cnt,cnt);
		intidx++;
	}
	document.form.k_d.selectedIndex = myDate-1;
}
function setDay(obj){
	obj = obj.form;
	var wkdata = obj.k_ym.options[obj.k_ym.selectedIndex].value;
	var k_ym = parseInt(wkdata.substring(0,4));
	var months = parseInt(wkdata.substring(4,6));
	
	var lastday = monthday(k_ym,months);
	var itemnum = obj.k_d.length;
	if (lastday-1 < obj.k_d.selectedIndex) {
		obj.k_d.selectedIndex = lastday-1;
	}
	obj.k_d.length = lastday;

	for (cnt = itemnum + 1;cnt <= lastday;cnt++) {
		obj.k_d.options[cnt - 1].text = cnt;
	}
}
function monthday(k_ym,months){
	var lastday = new Array(31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31);
	if (((k_ym % 4 == 0) && (k_ym % 100 != 0)) || (k_ym % 400 == 0)){
		lastday[1] = 29;
	}
	return lastday[months - 1];
}