实现效果：

 

 

 前端html代码：

<input type="text" class="form-control" name="keyword" placeholder="请输入关键词" value='{$keyword}' id="keyword"/>

<img src="__HOME__/img/search.png"  alt=""  class='searchBtn'/>

前端script代码：

                 <script>
                    $(function(){
                        $('.searchBtn').click(function(){
                            var keyword = $('#keyword').val();
                            if(!keyword){
                                alert("请输入搜索词")
                                return false;
                            }
                            window.location.href="/product?keyword=" + keyword; //搜索内容跳转页面
                        })
                    })
                 </script>

后端代码：

       //当前分类id  
        $cate_id = $child_id ? $child_id : $cate_id;
        $current_cate = M("Productcate")->where("id=$cate_id")->find(); //M实例化一个没有模型文件的Model  
        $this->assign('current_cate', $current_cate); 
        $c_ids = array();
        $children = D('Productcate')->catList($cate_id, '', false); //查找当前分类的所有子类
        foreach ($children as $k => $v) {
            $c_ids[] = $v['id'];
        }
        $where = '';
        if ($keyword = I('keyword')) {
            $where = " and title like '%{$keyword}%' ";//模糊查询标题
            $this->assign('keyword', $keyword);
        }


        $pro_list = $this->lists('Product', "  status = 1 and ((cate_id in(" . implode(',', $c_ids) . ")  ) $where  )", 'sort asc,id desc');
        $this->assign('list', $pro_list);