Fibonacci tail recursion

fibonacci

function fib(n) {
    var s = n1 = n2 = i = 1;
    for (; i < n; i++) {
        s = n1 + n2;
        n1 = n2;
        n2 = s;
    }
    return n1;
}

function fib2(n) {
    return function(n) {
        if (n === 0) return 0;
        if (n === 1) return 1;
        return arguments.callee(n - 1) + arguments.callee(n - 2);
    }(n);
}

function fib3(n) {
    return function(n1, n2, i) {
        return (i < n) ? arguments.callee(n2, n1 + n2, i + 1) : n1;
    }(0, 1, 1);
}

console.log(fib(2) + ',' + fib2(2) + ',' + fib3(2));
console.log(fib(4) + ',' + fib2(4) + ',' + fib3(4));
console.log(fib(5) + ',' + fib2(5) + ',' + fib3(5));