Calculate date of birth from age in JavaScript code example

Example 1: javascript get age

function getAge(dateString) 
{
    var today = new Date();
    var birthDate = new Date(dateString);
    var age = today.getFullYear() - birthDate.getFullYear();
    var m = today.getMonth() - birthDate.getMonth();
    if (m < 0 || (m === 0 && today.getDate() < birthDate.getDate())) 
    {
        age--;
    }
    return age;
}

Example 2: javascript work out age from date of birth

// To calculate age:
var year_born = prompt("Please enter your date of birth:", "Type here");
var d = new Date();
var n = d.getFullYear();
function getAge(birthYear){
	var currentDate = new Date();
    var currentYear = currentDate.getFullYear();
    age = currentYear - birthYear;
    return age;
}
calculatedAge = getAge(year_born);
alert("Hello, " + "you are " + calculatedAge + " years old!");

Example 3: age calculator javascript

function calculate_age(dob) { 
    var diff_ms = Date.now() - dob.getTime();
    var age_dt = new Date(diff_ms); 
  
    return Math.abs(age_dt.getUTCFullYear() - 1970);
}

console.log(calculate_age(new Date(1982, 11, 4)));

console.log(calculate_age(new Date(1962, 1, 1)));

Example 4: age calculator javascript

<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <title>JavaScript program to calculate age</title>
</head>
<body>

</body>
</html>

Tags:

Javascript Example

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