我有一个漂亮的答案，虽然它不是我的代码。不幸的是，我忘记了原来的帖子。

function calculateAge(y, m, d) {
    var _birth = parseInt("" + y + affixZero(m) + affixZero(d));
    var  today = new Date();
    var _today = parseInt("" + today.getFullYear() + affixZero(today.getMonth() + 1) + affixZero(today.getDate()));
    return parseInt((_today - _birth) / 10000);
}
function affixZero(int) {
    if (int < 10) int = "0" + int;
    return "" + int;
}
var age = calculateAge(1980, 4, 22);
alert(age);

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。

从naveen和原始OP的帖子中采用，我最终得到了一个可重用的方法存根，它接受字符串和/或JS Date对象。

我将其命名为gregorianAge()，因为这个计算准确地给出了我们如何使用公历表示年龄。即，如果月和日在出生年份的月和日之前，则不计算结束年。

/** * Calculates human age in years given a birth day. Optionally ageAtDate * can be provided to calculate age at a specific date * * @param string|Date Object birthDate * @param string|Date Object ageAtDate optional * @returns integer Age between birthday and a given date or today */ function gregorianAge(birthDate, ageAtDate) { // convert birthDate to date object if already not if (Object.prototype.toString.call(birthDate) !== '[object Date]') birthDate = new Date(birthDate); // use today's date if ageAtDate is not provided if (typeof ageAtDate == "undefined") ageAtDate = new Date(); // convert ageAtDate to date object if already not else if (Object.prototype.toString.call(ageAtDate) !== '[object Date]') ageAtDate = new Date(ageAtDate); // if conversion to date object fails return null if (ageAtDate == null || birthDate == null) return null; var _m = ageAtDate.getMonth() - birthDate.getMonth(); // answer: ageAt year minus birth year less one (1) if month and day of // ageAt year is before month and day of birth year return (ageAtDate.getFullYear()) - birthDate.getFullYear() - ((_m < 0 || (_m === 0 && ageAtDate.getDate() < birthDate.getDate())) ? 1 : 0) } // Below is for the attached snippet function showAge() { $('#age').text(gregorianAge($('#dob').val())) } $(function() { $(".datepicker").datepicker(); showAge(); }); <link rel="stylesheet" href="//code.jquery.com/ui/1.11.4/themes/smoothness/jquery-ui.css"> <script src="//code.jquery.com/jquery-1.10.2.js"></script> <script src="//code.jquery.com/ui/1.11.4/jquery-ui.js"></script> DOB: <input name="dob" value="12/31/1970" id="dob" class="datepicker" onChange="showAge()" /> AGE: <span id="age"><span>

moment.js还有一个可能的解决方案:

var moment = require('moment');
var startDate = new Date();
var endDate = new Date();
endDate.setDate(endDate.getFullYear() + 5); // Add 5 years to second date
console.log(moment.duration(endDate - startDate).years()); // This should returns 5

试试这个:

$('#Datepicker').change(function(){

var $bef = $('#Datepicker').val();
var $today = new Date();
var $before = new Date($bef);
var $befores = $before.getFullYear();
var $todays = $today.getFullYear();
var $bmonth = $before.getMonth();
var $tmonth = $today.getMonth();
var $bday = $before.getDate();
var $tday = $today.getDate();

if ($bmonth>$tmonth)
{$('#age').val($todays-$befores);}

if ($bmonth==$tmonth)
{   
if ($tday > $bday) {$('#age').val($todays-$befores-1);}
else if ($tday <= $bday) {$('#age').val($todays-$befores);}
}
else if ($bmonth<$tmonth)
{ $('#age').val($todays-$befores-1);} 
})

function age()
{
    var birthdate = $j('#birthDate').val(); // in   "mm/dd/yyyy" format
    var senddate = $j('#expireDate').val(); // in   "mm/dd/yyyy" format
    var x = birthdate.split("/");    
    var y = senddate.split("/");
    var bdays = x[1];
    var bmonths = x[0];
    var byear = x[2];
    //alert(bdays);
    var sdays = y[1];
    var smonths = y[0];
    var syear = y[2];
    //alert(sdays);

    if(sdays < bdays)
    {
        sdays = parseInt(sdays) + 30;
        smonths = parseInt(smonths) - 1;
        //alert(sdays);
        var fdays = sdays - bdays;
        //alert(fdays);
    }
    else{
        var fdays = sdays - bdays;
    }

    if(smonths < bmonths)
    {
        smonths = parseInt(smonths) + 12;
        syear = syear - 1;
        var fmonths = smonths - bmonths;
    }
    else
    {
        var fmonths = smonths - bmonths;
    }

    var fyear = syear - byear;
    document.getElementById('patientAge').value = fyear+' years '+fmonths+' months '+fdays+' days';
}