JSFiddle - React, Tailwind, and code Playground

HTML

<input type="text" id="input" /> <button type="button" onclick="alg();">Изчисли</button>
<div id="result"></div>

JavaScript

function alg() {
    var input = document.getElementById('input').value;
    var numbers = input.split(',');
    var count = numbers.length;
    var sum = 0;
    for(var i = 0; i < count; i++) {
        sum += numbers[i]|0;
    }
    
    var average = sum / count;
    
    var div = document.getElementById('result');
    div.innerHTML = 'Брой: ' + count + ' / Сума: ' + sum + ' / Средна стойност: ' + average;
}