还有两个选择:

// Int Age to Date as string YYY-mm-dd
function age_to_date(age)
{
    try {
        var d = new Date();
        var new_d = '';
        d.setFullYear(d.getFullYear() - Math.abs(age));
        new_d = d.getFullYear() + '-' + d.getMonth() + '-' + d.getDate();

        return new_d;
    } catch(err) {
        console.log(err.message);
    }
}
// Date string (YYY-mm-dd) to Int age (years old)
function date_to_age(date)
{
    try {
        var today = new Date();
        var d = new Date(date);

        var year = today.getFullYear() - d.getFullYear();
        var month = today.getMonth() - d.getMonth();
        var day = today.getDate() - d.getDate();
        var carry = 0;

        if (year < 0)
            return 0;
        if (month <= 0 && day <= 0)
            carry -= 1;

        var age = parseInt(year);
        age += carry;

        return Math.abs(age);
    } catch(err) {
        console.log(err.message);
    }
}

我只是不得不为自己写这个函数-接受的答案是相当好的，但IMO可以使用一些清理。这需要一个unix时间戳的dob，因为这是我的要求，但可以迅速适应使用字符串:

var getAge = function(dob) {
    var measureDays = function(dateObj) {
            return 31*dateObj.getMonth()+dateObj.getDate();
        },
        d = new Date(dob*1000),
        now = new Date();

    return now.getFullYear() - d.getFullYear() - (measureDays(now) < measureDays(d));
}

注意，我在measureDays函数中使用了31的固定值。所有计算所关心的是“年中的一天”是时间戳的单调递增度量。

如果使用javascript时间戳或字符串，显然需要删除1000的因子。

以下是计算年龄的简单方法:

//dob date dd/mm/yy 
var d = 01/01/1990


//today
//date today string format 
var today = new Date(); // i.e wed 04 may 2016 15:12:09 GMT
//todays year
var todayYear = today.getFullYear();
// today month
var todayMonth = today.getMonth();
//today date
var todayDate = today.getDate();

//dob
//dob parsed as date format   
var dob = new Date(d);
// dob year
var dobYear = dob.getFullYear();
// dob month
var dobMonth = dob.getMonth();
//dob date
var dobDate = dob.getDate();

var yearsDiff = todayYear - dobYear ;
var age;

if ( todayMonth < dobMonth ) 
 { 
  age = yearsDiff - 1; 
 }
else if ( todayMonth > dobMonth ) 
 {
  age = yearsDiff ; 
 }

else //if today month = dob month
 { if ( todayDate < dobDate ) 
  {
   age = yearsDiff - 1;
  }
    else 
    {
     age = yearsDiff;
    }
 }

如果你需要以月为单位的年龄(天是近似值):

birthDay=28;
birthMonth=7;
birthYear=1974;

var  today = new Date();
currentDay=today.getUTCDate();
currentMonth=today.getUTCMonth() + 1;
currentYear=today.getFullYear();

//calculate the age in months:
Age = (currentYear-birthYear)*12 + (currentMonth-birthMonth) + (currentDay-birthDay)/30;

如果年龄只是为了显示(可能不是100%准确)，下面的答案是一个很好的方法，但至少它更容易让你理解

function age(birthdate){
  return Math.floor((new Date().getTime() - new Date(birthdate).getTime()) / 3.154e+10)
}

这对我来说是最优雅的方式:

const getAge = (birthDateString) => { const today = new Date(); const birthDate = new Date(birthDateString); const yearsDifference = today.getFullYear() - birthDate.getFullYear(); 如果( 今天。getmonth () < birthDate.getMonth() || . getmonth ( (today.getMonth() === birthDate.getMonth() && today.getDate() < birthDate.getDate())) ) { 返回yearsDifference - 1; ｝ 返回yearsDifference; }; console.log (getAge (' 2018-03-12 '));