//array.splice(a, b, c);
//第一个参数a表示：操作的开始位置 ，第二个参数b表示：从第a个位置开始向后删除b各个元素，第三个元素表示插入的元素（如果c不存在则表示这个函数是用来删除用的），替换操作如何实现呢，就是删除你想替换的那个，然后再插入，下面给出demo，和操作结果

alert('test delete 5 items in [ '+lang+' ]from pos 1 ');
                        var insert2 = lang.splice(1, 5);
                        alert('deleted items ['+insert2+']'); // 
                        alert('leave ['+lang+']'); //"php", "java", "javascript", "111", "222", "333"
                        
                        lang = ["php", "java", "javascript", "111", "222", "333"];
                        
                        alert('test insert 1 item c++ in [ '+lang+' ] from pos 1 ');
                        insert2 = lang.splice(1, 0,'c++');
                        alert('delete items ['+insert2+']'); // 
                        alert('resultarray ['+lang+']'); 
                        
                        
                        lang = ["php", "java", "javascript", "111", "222", "333"];
                        
                        alert('test replace 1 item  java to  c++ in [ '+lang+' ] ');
                        insert2 = lang.splice(1, 1,'c++');
                        alert('delete items ['+insert2+']'); // 
                        alert('resultarray ['+lang+']'); 

控制台输出如下操作结果：

test delete 5 items in [ php,java,javascript,111,222,333 ]from pos 1 
 deleted items [java,javascript,111,222,333]
 leave [php]
 test insert 1 item c++ in [ php,java,javascript,111,222,333 ] from pos 1 
 delete items []
 resultarray [php,c++,java,javascript,111,222,333]
 test replace 1 item  java to  c++ in [ php,java,javascript,111,222,333 ] 
 delete items [java]
 resultarray [php,c++,javascript,111,222,333]

github：https://github.com/zxzxzxygithub/jssplicetest/tree/master