gistfile1.js

/* iterative fibonacci sequence O(n) */
function fibo(n) {
    var fiboArr = [0, 1];
    for (var i = 1; i < n; i++) {
        fiboArr.push(fiboArr[i - 1] + fiboArr[i]);
    }
    return fiboArr;
}

function fiboSum(n) {
    var sum = 0,
        arr = fibo(n);
    for (var i = 0; i < arr.length; i++) {
        if (arr[i] > n)
            break;
        if (arr[i] % 2 == 0) {
            sum += arr[i];
        }
    }
    return sum;
}