Date.prototype.AddDays = function (days) {
    days = parseInt(days, 10);
    return new Date(this.valueOf() + 1000 * 60 * 60 * 24 * days);
}

例子

var dt = new Date();
console.log(dt.AddDays(-30));
console.log(dt.AddDays(-10));
console.log(dt.AddDays(-1));
console.log(dt.AddDays(0));
console.log(dt.AddDays(1));
console.log(dt.AddDays(10));
console.log(dt.AddDays(30));

结果

2017-09-03T15:01:37.213Z
2017-09-23T15:01:37.213Z
2017-10-02T15:01:37.213Z
2017-10-03T15:01:37.213Z
2017-10-04T15:01:37.213Z
2017-10-13T15:01:37.213Z
2017-11-02T15:01:37.213Z

这个答案中的任何一个例子似乎都不适用于日光节约时间调整日。在这些日子里，一天的小时数不是24小时(是23小时还是25小时，取决于你是“向前跳”还是“向后跳”)。

下面的AddDays javascript函数说明了夏令时:

function addDays(date, amount) {
  var tzOff = date.getTimezoneOffset() * 60 * 1000,
      t = date.getTime(),
      d = new Date(),
      tzOff2;

  t += (1000 * 60 * 60 * 24) * amount;
  d.setTime(t);

  tzOff2 = d.getTimezoneOffset() * 60 * 1000;
  if (tzOff != tzOff2) {
    var diff = tzOff2 - tzOff;
    t += diff;
    d.setTime(t);
  }

  return d;
}

以下是我用来测试该功能的测试:

    var d = new Date(2010,10,7);
    var d2 = AddDays(d, 1);
    document.write(d.toString() + "<br />" + d2.toString());

    d = new Date(2010,10,8);
    d2 = AddDays(d, -1)
    document.write("<hr /><br />" +  d.toString() + "<br />" + d2.toString());

    d = new Date('Sun Mar 27 2011 01:59:00 GMT+0100 (CET)');
    d2 = AddDays(d, 1)
    document.write("<hr /><br />" +  d.toString() + "<br />" + d2.toString());

    d = new Date('Sun Mar 28 2011 01:59:00 GMT+0100 (CET)');
    d2 = AddDays(d, -1)
    document.write("<hr /><br />" +  d.toString() + "<br />" + d2.toString());

最简单的方法是转换为毫秒，然后加上1000*60*60*24毫秒，例如:

var tomorrow = new Date(today.getTime()+1000*60*60*24);

这个方法更简单， 它会以简单的yyyy-mm-dd格式返回日期，就是这个

function incDay(date, n) {
    var fudate = new Date(new Date(date).setDate(new Date(date).getDate() + n));
    fudate = fudate.getFullYear() + '-' + (fudate.getMonth() + 1) + '-' + fudate.toDateString().substring(8, 10);
    return fudate;
}

例子:

var tomorrow = incDay(new Date(), 1); // the next day of today , aka tomorrow :) .
var spicaldate = incDay("2020-11-12", 1); // return "2020-11-13" .
var somedate = incDay("2020-10-28", 5); // return "2020-11-02" .

Note

incDay(new Date("2020-11-12"), 1); 
incDay("2020-11-12", 1); 

将返回相同的结果。

将当前日期的增量分配给其他变量

 let startDate=new Date();
 let endDate=new Date();    
 endDate.setDate(startDate.getDate() + 1)
 console.log(startDate,endDate)

未来5天:

var date = new Date(),
d = date.getDate(),
m = date.getMonth(),
y = date.getFullYear();


for(i=0; i < 5; i++){
var curdate = new Date(y, m, d+i)
console.log(curdate)
}