如何获得ajax返回id隐藏变量..在请求页面

我需要得到最后插入id从控制器到ajax成功函数......我想自定义产品，当用户按添加到购物车ajax被执行和设计是要插入数据库....在插入数据库后，我得到最后插入id.....插入…但需要最后插入id....当用户按下隐藏字段中的添加到购物车按钮时…
这是我的Ajax代码。

$('#store').click(function(){
    $.ajax({                                      
      type: "POST",              
      url: ajax_url_store,       
      data: {action: 'store', views: JSON.stringify(thsirtDesigner.getProduct()) },
      success: function(data) {
                            if(parseInt(data) > 0) {
                            //successfully added..here i am getting last insert id...
                            // and i want to pass that in hidden variable.....
                            // on view page.....
                                }
                                else {
                                       document.getElementById('succes-message').innerHTML = 'You Design has not Been                                                                                                   Saved';             
                                }
                        },
                        error: function() {
                            //alert('some error has occured...');
                        },
                        start: function() {
                            //alert('ajax has been started...');    
                        }
          });
});

my CI controller

public function saveData(){
            if($this->input->post('action') == 'store') {
                $views = $this->input->post('views');
                $id = $this->product_model->save($views);
                $data = array('cust_id'=>$id); 
                $this->session->set_userdata($data);    
                if($id !=''){
                    header('Content-Type: application/json');
                    echo json_encode($id);
                    }
                }
            }