*冒泡排序

var arr = [8,2,6,4,5]
for (var i=0; i<arr.length-1; i++) {
   console.log("比较轮数："+(i+1));
   for (var j=0; j<arr.length-1-i; j++) {
       if (arr[j] > arr[j+1]) {
           var temp = arr[j];
           arr[j] = arr[j+1];
           arr[j+1] = temp;
       }
       console.log("每轮比较次数:"+ (j+1));
   }
   console.log(arr);
}