js获取指定日期之前/之后的某天——tool

Posted 2020-10-12 游龙翔隼

var date_getPointDate = function (currDate, num) {  //num表示天数，接受正负数
  num = Math.floor(num);
  var symbol = ‘/‘;
  if(currDate.indexOf(‘-‘)>-1){
    symbol = ‘-‘;
  }else if(currDate.indexOf(‘.‘) > -1){
    symbol = ‘.‘;
  }
  var myDate = new Date(currDate);
  var lw = new Date(Number(myDate) + 1000 * 60 * 60 * 24 * num); //num天数
  var lastY = lw.getFullYear();
  var lastM = lw.getMonth()+1;
  var lastD = lw.getDate();
  var startdate=lastY+ symbol +(lastM<10 ? "0" + lastM : lastM)+ symbol +(lastD<10 ? "0"+ lastD : lastD);
  return startdate;
}

console.log(date_getPointDate("2017-10-24", 30))  //2017-11-23
console.log(date_getPointDate("2017/10/24", -30)) //2017/09/24
// 调用规则 :
// 指定日期n天前日期：date_getPointDate("2017/11/26", -30)　　//返回"2017/10/27"

// 指定日期n天后日期：date_getPointDate("2017/10/27", 30)　　//返回"2017/11/26"