simple javascript generator without yield

euler.js

// Project Euler problem 2
function makeFibSequence(a, b) {
  // or ...
  // var a = 0;
  // var b = 1;
  return function () {
    var next = a + b;
    a = b;
    b = next;
    return next;
  };
}

var go2 = function () {
  var max = 4000000;
  var current = 0;
  var sum = 0;
  var nextFib = makeFibSequence(0, 1); // makeFibSequence();

  while (current < max) {
    current = nextFib();
    if (current % 2 == 0) sum += current;
  }

  return sum;
};

console.log(go2());