javascript之冒泡算法

<script>
        var arr=[1,30,20,40,21,31,10];
        //orient为true时，为升序排列，为false时，为降序排列
        function change(arr,orient,arrLength){
            var i=0;
            var arrChange;
            for(i=0;i<(arrLength-1);i++){
                if(arr[i]>arr[i+1]){
                    if(orient){
                        arrChange=arr[i];
                        arr[i]=arr[i+1];
                        arr[i+1]=arrChange;
                    }
                }else{
                    if(!orient){
                        arrChange=arr[i];
                        arr[i]=arr[i+1];
                        arr[i+1]=arrChange;
                    }
                }
            }
        }
        function changeNum(arr,orient){
            var j=arr.length;
            console.log(arr);
            for(j;j>1;j--){
                change(arr,orient,j);
                console.log("第"+(arr.length-j+1)+"次"+"|"+arr.join("|"));
            }
        }
        changeNum(arr,false);
    </script>