function getNowFormatDate() {

    var date = new Date();

    var seperator1 = "-";

    var seperator2 = ":";

    var month = date.getMonth() + 1;

    var strDate = date.getDate();

    if (month >= 1 && month <= 9) {

        month = "0" + month;

    }

    if (strDate >= 0 && strDate <= 9) {

        strDate = "0" + strDate;

    }

    var currentdate = date.getFullYear() + seperator1 + month + seperator1 + strDate

            + " " + date.getHours() + seperator2 + date.getMinutes()

            + seperator2 + date.getSeconds();

    return currentdate;

}

var date = new Date();

//这里的60就是你要加的天数，减也可以。年、月会相应加上去，值得注意的是date.getMonth()得到的月份比实际月份小1，所以实际月份是(date.getMonth()+1)

date.setDate(date.getDate() + 60);

console.log(date.getFullYear() +"-"+ (date.getMonth()+1) +"-"+ date.getDate());