Age calculator app using vanilla Javascript

I'm not 100% sure what you mean by animating the numbers but,

if you're referring to the " - -" and replacing it with the results, you should create an element : <span id="yearsResult">- -</span>

then in Javascript you're going to target this ID and store it like this:

let years = document.getelementbyid(yearsResult);

Once stored, you're going to retrieve the results from (what I assume should have been the function calculating the years) and replace the span value with the results using basic dom manipulation. Store the results in a variable so you can then use template literals to display the results. Lets say you stored years in a variable called "calculatedYears". You can then do :

years.innerHTML = ${calculatedYears};

and your span value will now display whatever the calculatedYears value returned from the calculation function.

Hope this helped.

Do you want to create a random generating effect, where a random number is displayed before the actual result is revealed? I've actually implemented that using the Math.random, Set Interval, and Set Timeout functions.

function randomNumber() {
function genRandomNum() {
const randomNumber = Math.floor(Math.random() * 100);
numField.textContent = randomNumber; 
}

const interval = setInterval(genRandomNum, someTime); // Call genRandomNum every someTime milliseconds

setTimeout(() => {
clearInterval(interval); // Stop calling genRandomNum after someTime milliseconds
}, someTime);
}