二分查找算法

var arr = [ 2, 2, 3, 4, 8, 9, 10 ];function binSearch(arr,data) {  var upperBound = arr.length - 1;  var lowerBound = 0;  while(lowerBound<=upperBound){//不要忘记添加循环    var mid = Math.floor((upperBound+lowerBound)/2);    console.log("当前中点："+mid)    if(arr[mid]<data){      lowerBound = mid+1;    }else if(arr[mid]>data){      upperBound = mid-1;    }else{      return mid;    }  }  return -1;}console.log(binSearch(arr,8));