fem-binary-search.js

function binarySearch(list, item) {
    var min = 0;
    var max = list.length - 1;
    var guess;

    while (min <= max) {
        guess = Math.floor((min+max)/2);

        if (list[guess] === item) {
            return guess;
        }
        else {
            if (list[guess] < item) {
                min = guess + 1;
            }
            else {
                max = guess - 1
            }
        }
    }

    return -1;
}

binarySearch([2,6,7,90,103], 90);