Fibonacci Sequence is the series of numbers: 0, 1, 1, 2, 3, 5, 8, 13, 21, 34. iFibonacci(6) => 8

iFibonacci.js

// iFibonacci(0) = 0           => 0
// iFibonacci(1) = 1           => 1
// iFibonacci(2) = 1           => 1
// iFibonacci(3) = 1 + 1       => 2
// iFibonacci(4) = 1 + 2       => 3
// iFibonacci(5) = 2 + 3       => 5
// iFibonacci(6) = 3 + 5       => 8

var iFibonacci = function(num){
	var num1 = 0;
	var num2 = 1;
	var counter = 1;
	while(num !== counter){
		var temp = num2;
		num2 += num1; 
		num1 = temp;
		counter ++;
	}
	return num2; 
};

iFibonacci(6);