获取第n天日期

function datezh(s){
return s = s>9 ? s:"0"+s
}

function dateTime(t){
var getNowTime = vm.getServerTime.replace(/-/g,"/");//vue  vm.getServerTime获取到的服务器时间
var d = new Date(getNowTime);
//var d = new Date();
var year = d.getFullYear();
var month = d.getMonth()+1;
var getdate = d.getDate();
var day = d.getDay();
var date2 = new Date(d);
        date2.setDate(d.getDate() + t);
var day = date2.getDay()
switch (day){
case 1:
day="一";
break;
case 2:
day="二";
break;
case 3:
day="三";
break;
case 4:
day="四";
break;
case 5:
day="五";
break;
case 6:
day="六";
break;
case 0:
day="天";
break;
}

return time2 = date2.getFullYear()+"年"+datezh((date2.getMonth()+1))+"月"+datezh(date2.getDate())+"日"+"(星期"+day+")";
}