Javascript Calculate Age from HTML input date type

Question

I am trying to calculate age using Javascript. The choose their date of birth from an HTML date input type and his/her age should be displayed. How can Javascript use the HTML Date input type data and calculate age?

Below is the HTML

<html>
<head>
<title> Sample Date of Birth Registration</title>

<script type="text/javascript" src="formiteration6.js"></script>
</head>
<body>
<h1>Birth Registration</h1>
<hr />
<form id ="inputFrom">
 <label for="size_1">D.O.B:</label><input type="date" name="size" id="birthDate" value="dd/mm/yy"  />
 <input type='button' onclick='regBirth()' value='Add new person' />
 </form>
 <hr />
<table id="details">
  <tr>
  <th>Date of Birth</th>
  <th>Age</th>
  </tr>

</table>
<h4>Statistics</h1>
<hr />
<h5><b>Total Count:</b></h5>
<p id="count"></p>

</body>
</html>

And Javascript is here

var allPeople = [];

function regBirth() {
    'use strict';
    var myArray = {};

    var actualDob = myArray.actualBirthDate;
    actualDob = document.getElementById('birthDate').value

    allPeople.push(myArray);

    var inputForm = document.getElementById("inputFrom").reset();
    var tabularForm = document.createDocumentFragment();
    var tablerow = document.createElement('tr'); 

    var dob = document.createElement('td');
    dob.innerHTML = actualDob;
    tablerow.appendChild(dob);

    tabularForm.appendChild(tablerow); 
    document.getElementById("details").appendChild(tabularForm);

    var totalPeople = allPeople.length;

    document.getElementById("count").innerHTML=totalPeople;
}

See https://stackoverflow.com/a/7091965/1722529 — first, get difference between current year and the year of birth. Then, if current month number is less than birth month number, subtract 1 from year difference and use the result as age. — Matvey Andreyev, Apr 05 '18 at 12:07

Vinod · Answer 1 · 2014-03-16T07:31:18.410

0

Get Today's Date using new Date()

Get Date of Birth using new Date(datestring)

Get Year from both Dates using getFullYear()

Now find the Difference between two Years.

Fiddle Demo

edited Mar 16 '14 at 07:31

answered Mar 16 '14 at 06:41

Vinod

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Is is like this? var currentDate = new Date(); var birth_date = new Date(actualDob); var currentYear = currentDate.getFullYear(); var myBirthYear = birth_date.getFullYear(); var myAge = currentYear - myBirthYear; document.getElementById("age").innnerHTML = myAge; – IslandKing Mar 16 '14 at 07:04
It's not displaying here: var myAge = currentYear - myBirthYear; document.getElementById("age").innnerHTML = myAge; in the HTML page – IslandKing Mar 16 '14 at 07:07
@IslandKing document.getElementById("age").value=myAge – Vinod Mar 16 '14 at 07:20
@Vinod Not that simple. Consider the following: on Jan 2nd, 2018, your code has been run on a birth date Aug 01, 1980. The person's age is still 37 by our rules on Jan, 2nd, 2018, but your code will tell the age as 38 already. – Matvey Andreyev Apr 05 '18 at 11:48

score 0 · Answer 2 · answered Aug 22 '22 at 11:14

in js

// Make a button that display the current date and time in local format on the page. 


function mydateis(){
    const d = new Date();
let text = d.toLocaleString();
document.getElementById("date").innerHTML = text;



var year_born = prompt("Please enter your date of birth:", 1998);
var month_born = prompt("Please enter your month:", 1);
var month_day = prompt("Please enter your day:", 1);
 

function getAge(birthYear,month_born,month_day){
    var currentDate = new Date();
    var currentYear = currentDate.getFullYear();
    var currentmonth = currentDate.getMonth();
    var currentday = currentDate.getDate();
    console.log(currentDate);
    console.log(currentDate.getDate());
    age = currentYear - birthYear;
    month = currentmonth - month_born;
    day = currentday - month_day;
    return age,month,day;
}

calculatedAge = getAge(year_born,month_born,month_day);
 document.getElementById("yearsold").innerHTML ="you have yeyre is" + age+ "  and  "+month+"  month and  days is  "+day ;


}

in html

<button onclick="mydateis()">date is </button>
<h4>hekoo date is </h4>
<p id="date"></p>
<p id="yearsold"></p>

the out bot is

Javascript Calculate Age from HTML input date type

2 Answers2