Sum of even Fibonacci numbers.

Counts the sum of even numbers in a Fibonacci series up to the entered value. Based on Project Euler problem number 2 (https://projecteuler.net/problem=2)

by Uzair Mehmood

HTML

<label for="input">Count sum upto :</label>
<input type="text" id="input" />
<hr>
<p id="output"></p>

JavaScript

$("#input").change(function(){
    var fibS = [1,2];
    var sum = 2;
    for (var i=2;;i++){
        var nextElem = fibS[i-1]+fibS[i-2];
        if (nextElem >= $(this).val()){
            break;
        }else{
            fibS.push(nextElem);
            if (nextElem % 2 === 0){
                sum += nextElem;
            }
        }
    }
    $("#output").text(sum);
});