JavaScript exercise: Find the highest Fibonacci number under 100

Highest_Fibonacci_Number_Under_100

//Return to me the highest Fibonacci number between 0 and 100
//1,2,3,5,8,13,21,34,55,89

var sum = 0;
var arr = [];

var fibo = function(num1, num2) {
    sum = num1 + num2;
    console.log('num1: ' + num1 + ' + num2: ' + num2 + ' = sum: ' + sum);

    if (sum < 100) {
      arr.push(sum);
      num1 = num2;
      num2 = sum;
      fibo(num1,num2);
    }
};

fibo(0,1);
console.log("Highest Fibonacci number under 100: " + arr.pop());