In this tutorial, we will see how to calculate date of birth from age in jQuery. You can use the below code snippet to create the tool as well. To calculate date of birth from age in jQuery we need to use Jquery and html.
Code to calculate date of birth from age in jquery
function getDobFromAge(){
//Get the current date from Date object first
var now = new Date();
//To calculate user dob we need to first get the age from user as input
var age = parseInt($('#age-input').val());
//now we will calculate the birth year
var birthYear = now.getFullYear() - age;
//lets, Create the birth date object to store the birthdate
var birthDate = new Date(birthYear, now.getMonth(), now.getDate());
//We will output the birth date in the format YYYY-MM-DD on console
console.log(birthDate.toISOString().slice(0,10));
//we are checking for valid input to check for invalid input value like blank or negative age, in that case will output invalid age on
//console
if (isNaN(age) || age <= 0) {
console.log("Invalid age entered.");
}
//Add another check for birth year before 1900 if os will output it as invalid or not supported one
if (birthYear < 1900) {
console.log("Birth year before 1900 is not supported.");
}
//Add another check for future birth year which should not be the case
if (birthYear > now.getFullYear()) {
console.log("Age entered corresponds to a future birth year.");
}
}
Index.html file code to call above function
<!DOCTYPE html>
<html>
<head>
<title>Calculate Date of Birth from given Age</title>
</head>
<body>
<label for="age-input">Enter Age:</label>
<input type="number" id="age-input" name="age-input">
<button onclick="geDobFromAge()">Calculate DOB</button>
<br>
<label for="dob-output">Date of Birth:</label>
<span id="dob-output"></span>
<script src="https://code.jquery.com/jquery-3.6.0.min.js"></script>
<script src="age-fromdob.js"></script>
</body>
</html>Code Explanation to calculate age from date of birth
In the above code, we are using jquery and html. from html page we are calling one javascript function which will execute the logic of calculating age from dob.
The JavaScript code provided provides a function called “getDobFromAge()” which determines a date of birth for users based on age input and produces results in YYYY-MM-DD format.
To obtain an age input value from the user, this function uses jQuery to select an HTML input field with ID “age-input”.
After computing their birth year by subtracting their age from current year, their date object also contains month and day details as part of this new date object.
A date object is then converted to a string using “toISOString(),” with its first 10 characters extracted using “slice().”
Additionally, this function features input validation to detect any invalid input values.
For instance, it checks if age input is valid and greater than zero before printing out an error message to console if an invalid value was entered.
Likewise, this function checks whether calculated birth year predating 1900 and prints an error message accordingly.
The code also includes an HTML file with an input field to collect user age information, a button to trigger “calculateDOB()”, and a span element displaying calculated date of birth results.
Furthermore, script tags include links to both the jQuery library and JavaScript file with “getDobFromAge()” functionality.
FAQ
What is the algorithm to calculate age from date of birth?
//now we will calculate the birth year
var birthYear = now.getFullYear() - age;
//lets, Create the birth date object to store the birthdate
var birthDate = new Date(birthYear, now.getMonth(), now.getDate());What data type is date of birth in JavaScript?
Its date data type in date of birth in JavaScript.
Conclusion
Conclusions : In summary we saw how to calculate date of birth from age in jquery, this JavaScript code defines a function which takes user age input and calculates their date of birth in accordance with a prescribed format. It includes input validation checks to catch any invalid input values while also displaying error messages to the console. An accompanying HTML file provides a user interface where they can input their age and view their calculated date of birth – providing another example of how JavaScript can be leveraged for calculations and input validation in web development projects.
Checkout full code here at SLB-Github
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