Assignment-EvenFibonacciNumbersBelow4Million.html

<h1>Sum of Even Fibonnaci Numbers Below ???</h1>
Threshold
<input type="number" id="Threshold" value="4000000">
<input type="button" value="Go" onclick="Go()">
<h2 id="Answer"></h2>

<script>
    //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 thresholdBox = document.getElementById("Threshold");
    var answerTag = document.getElementById("Answer");

    function Go() {
        var sum = 0;
        var firstNumber = 0;
        var secondNumber = 1;
        while(secondNumber < thresholdBox.valueAsNumber) {
            var nextNumber = firstNumber + secondNumber;
            //console.log(firstNumber.toLocaleString() 
            //    + " + " 
            //    + secondNumber.toLocaleString() 
            //    + " = " + nextNumber.toLocaleString() 
            //    + "\n");
            if (nextNumber % 2 === 0) {
                sum = sum + nextNumber;
                //console.log("sum: " + sum.toLocaleString());
            }
            firstNumber = secondNumber;
            secondNumber = nextNumber;
        }
        answerTag.innerHTML = "Sum of even values: " + sum.toLocaleString();
    }
</script>