Javascript での splice() の正しい使用法

arrayObject.splice(index,deleteCount,item1,.....,itemX)

     <script>
          arr1=[9,2,6,4,5];
          res1=arr1.splice(2);
          console.log(res1);//[6, 4, 5]被删除的元素
          console.log(arr1);//[9,2]剩余元素

          arr2=[9,2,6,4,5];
          res2=arr2.splice(2,2);
          console.log(res2);//[6, 4]被删除的元素
          console.log(arr2);//[9,2,5]剩余元素
    </script>

    <script>
          arr3=[9,2,6,4,5];
          console.log(arr3);
          result=arr3.splice(1,0,99,10);
        //   console.log(result);空数组
          console.log(arr3);
          result=arr3.splice(2,0,...[111]);
          console.log(arr3);
    </script>

    <script>
          arr4=[1,2,3,4,5];
          res=arr4.splice(1,3,...[88,99,44]);
          console.log(arr4);
    </script>