projecteuler.net Problem 2: Fibonacci sum. A JavaScript solution.

fibonacci.js

/*
projecteuler.net
Problem 2
Each new term in the Fibonacci sequence is generated by adding the previous two terms. By starting with 1 and 2, the first 10 terms will be:

1, 2, 3, 5, 8, 13, 21, 34, 55, 89, ...

By considering the terms in the Fibonacci sequence whose values do not exceed four million, find the sum of the even-valued terms.
*/

var fibonacci = [0, 1, 1, 2];
var i = 4;
var sum = 0;

while (fibonacci[i-1] + fibonacci[i-2] <= 4000000){
  fibonacci[i] = fibonacci[i-1] + fibonacci[i-2];
  i += 1;
}

for (var j in fibonacci){
  sum += fibonacci[j];
}

console.log(sum);