数组多功能splice()方法的插入，删除，替换

多功能splice()插入、删除、替换

  <script type="text/javascript">
         var arr=['A','B','C','D','E','F','G'];
         arr.splice(3,2,'苹果','葡萄');  //替换一些项
         console.log(arr);
    </script>

  <script type="text/javascript">
         // 更改一些项
         var arr=['A','B','c','d','e','f','g']
         arr.splice(3,2,'x','y','x','斯密码'); //更改一些项
         console.log(arr);

    </script>

 <script type="text/javascript">
         var arr=['a','b','c','d','e','f','g']
            arr.splice(2,1,'哈哈');//更改一个项
            console.log(arr);
    </script>

  <script type="text/javascript">
         var arr=['a','b','c','d','e','f','g'];
         arr.splice(2,4) //没有东西可以替换，就直接删除
         console.log(arr);

    </script>

    <script type="text/javascript">
         var arr=['a','b','c','d','e','f','g'];
         arr.splice(2);
         console.log(arr);
    </script>

    <script type="text/javascript">
         var arr=['a','b','c','d','e','f','g'];
         arr.splice(2,0,'嘻嘻','哈哈'); //插入一些项
         console.log(arr);
    </script>

二、案例 ：删除数组最后五项

    <script type="text/javascript">
         //删除数组最后五项
         var arr['a','b','c','d','e','f','g'];
         arr.pop();
         arr.pop();
         arr.pop();
         arr.pop();
         arr.pop();
         //简化为
         for(var i=0; i<arr.length; i++;){
            arr[i].pop();
         }
         //也可以
         arr.splice(-5);
         console.log(arr);
    </script>