js 日期 当天 和 加上几天

简单的显示第几天: 

 function showdate(n)
{
var uom = new Date();
uom.setDate(uom.getDate()+n);
uom = uom.getFullYear() + "-" +   (uom.getMonth()+1) + "-" + uom.getDate();
return uom;
}

window.alert("今天是："+showdate(0));
window.alert("昨天是："+showdate(-1));
window.alert("明天是："+showdate(1));
window.alert("10天前是："+showdate(-10));
window.alert("5天后是："+showdate(5)); 

 

返回格式化的日期,年份或日期不是2位则补位2位:如"2009-05-12"

function getOtherDate(n) {
	var nn = new Date();
	nn.setDate(nn.getDate()+n);
	year1 = nn.getYear();
	mon1 = nn.getMonth() + 1;
	date1 = nn.getDate();
	var monstr1;
	var datestr1
	if (mon1 < 10)
		monstr1 = "0" + mon1;
	else
		monstr1 = "" + mon1;

	if (date1 < 10)
		datestr1 = "0" + date1;
	else
		datestr1 = "" + date1;
	return year1 + "-" + monstr1 + "-" + datestr1;
}