function initBirthday(arg0,arg1,arg2){
	var now = new Date();
	var year = now.getFullYear();
	var select = document.getElementById(arg0);
	for(var i = year-3; i>(year-100); i--){
		var y=document.createElement('option');
		y.text = i;
		y.value = i;
		select.options.add(y);
	}
	var selectMonth = document.getElementById(arg1);
	for(var i=1; i<=12; i++){
		var opt = document.createElement('option');
		opt.text = i;
		opt.value = i;
		selectMonth.options.add(opt);
	}
	var days = CalDays(year-3,1);
	//alert('days' + days);
	var selectDay = document.getElementById(arg2);
	for(var i = 1; i<=days; i++){
		var opt = document.createElement('option');
		opt.text = i;
		opt.value = i;
		selectDay.options.add(opt);
	}
}

var initDay = function(arg0,arg1,arg2){
	var selectYear = document.getElementById(arg0);
	var selectMonth = document.getElementById(arg1);
	var selectDay = document.getElementById(arg2);
	
	var year = eval(selectYear.options[selectYear.selectedIndex].text);
	var month = eval(selectMonth.options[selectMonth.selectedIndex].text);
	//alert(selectYear.selectedIndex);//下标从0开始
	var days = CalDays(year,month);
	//selectDay.options.length = 0;
	var nowLength = selectDay.length;
	//alert("nowLength:" + nowLength);
	//删除多出的选项
	if(nowLength > days){
		for(var i=days;i<nowLength;i++){
			selectDay.remove(days);
		}
	} else if(nowLength < days){//增加缺少的选项
		for(var i=nowLength;i<days;i++){
			var opt = document.createElement('option');
			opt.text = i+1;
			opt.value = i+1;
			selectDay.options.add(opt);
		}
	}
}
/**
 *获得当前年月的天数
 */
function CalDays(year,month){
	var days=0;
	switch(month){
		case 1: case 3: case 5: case 7: case 8: case 10: case 12: days=31;break;
		case 4: case 6: case 9: case 11: days=30;break;
		case 2: if(isLeapYear(year)) days=29;else days=28;break;
	}
	return days;
}
/**
 *判断是否是闰年
 */
function isLeapYear(year){
	return ((year %4==0 && year %100!=0) || (year %400==0));
}

function GetDateString(obj){ 
	var oDate = obj;
          
    var month = oDate.getMonth() + 1; 
    if (month <= 9){
    	month = "0" + month;
    }
            
   	var day = oDate.getDate(); 
    if (day <= 9){ 
    	day = "0" + day;
    }
    var sDate = oDate.getFullYear() + "-" + month + "-" + day;
    return sDate;
}