On the sorting algorithm

Bubble Sort

　　<script>

        // Principle: traverse the entire array, compare and swap back and forth adjacent elements

        was arr = [5, 3, 4, 1, 2];

        for (var i = 0; i < arr.length - 1; i++) {

            for (var j = 0; j < arr.length - i - 1; j++) {

                var temp = arr[j];

                arr [j] = arr [j + 1];

                arr[j + 1] = temp;

            }

        }

        // key points: two-cycle  

        @ Layer: i <arr.length -1  

        Inner @: j <arr.length - i - 1

        console.log(arr);

    </script>