var arr = [9, 2, 3, 15, 5];
        function find() {
            var max = arr[0], min = arr[0];
            var maxindex = 0;
            var minindex = 0;
            for (var i = 0; i < arr.length; i++) {
                if (arr[i] > max) {
                    max = arr[i];
                    maxindex = i;
                } else if (arr[i] < min) {
                    min = arr[i];
                    minindex = i;
                }
            }
            console.log("最大值为：" + max + "位置为：" + maxindex);
            console.log("最小值为：" + min + "位置为：" + minindex);
        }

        find();