javascript - 根据输入和日期对象计算出一个人的年龄

Question

在获取用户输入的出生信息后，我想将他们的年龄转换为毫秒，然后从当前日期中减去它以返回他们的年龄，我该如何正确执行此操作？:

var birthYear = parseInt(prompt ('Enter your birth year:'));
var birthMonth = prompt ('Enter the name of the month of birth:');
var birthDay = parseInt(prompt ('Enter your day of birth as an integer:'));
var milliDay = 1000*60*60*24; //Milliseconds in a day
monthAbb = 'janfebmaraprmayjunjulaugsepoctnovdec';
chineseZod = 12;
zodCycle = 1924; //Chinese Zodiac Cycle
var monthArr = new Array(11);


monthArr [0] = "jan";
monthArr [1] = "feb";
monthArr [2] = "mar";
monthArr [3] = "apr";
monthArr [4] = "may";
monthArr [5] = "jun";
monthArr [6] = "jul";
monthArr [7] = "aug";
monthArr [8] = "sep";
monthArr [9] = "oct";
monthArr [10] = "nov";
monthArr [11] = "dec";

var monthNum = monthAbb.indexOf(birthMonth.slice(0, 3).toLowerCase()) / 3; 
alert(monthNum);
var d = new Date (birthYear, monthNum, birthDay);
alert(d);

Answer 1

var today=new Date();
var millisec=today.getTime();
alert(millisec);

这将以毫秒为单位返回时间。
例如计算年龄:-

    var dt1 = new Date();
    var age = (dt1.getTime() - d.getTime()) / (60 * 60 * 24 * 1000);