二分查找法

  <script>
        function m(num, list) {

            var low = 0;
            var height = list.length - 1;

            while (low <= height) {
                var midder = parseInt((low + height) / 2)
                if (num == list[midder]) {
                    return midder;
                } else if (num > list[midder]) {
                    low = midder + 1
                } else {
                    height = midder - 1
                }
            }
            return -1;

        }
        var s = m(16, [1, 2, 3, 4, 5, 6, 7, 8,9,10,11,12, 13, 14, 15, 16]);
        console.log(s);
    </script>