想把传统的type="text"实现type="textarea"的效果，比如下设置为type="textarea"显然不生效：

 <input value="{$xinxianshi['mingcheng']}"  type="text" name="mingcheng" placeholder="实例格式：1999-10-14" id="inputbirthday" >

可以用以下方法实现：
view

 <form action="{:U('Xinxianshi/bianji')}" method="post" enctype="multipart/form-data">
                    <input type="hidden" name="id" value="<?=$xinxianshi['id']?>">
                        <div class="box-header">
                            <h3 class="box-title"></h3>
                            <a href="{:U('list')}" class="btn btn-default pull-right">新鲜事列表</a>
                        </div><!-- /.box-header -->

                        <div class="box-body">
<!-- s -->
 <tr><TD align="right" width=120 height=60>留言内容</TD><td></td></tr> 
                            <!-- d -->
                            <div class="form-group">
                                <label for="inputSubject"></label>
                                <input value="{$xinxianshi['neirong']}"  type="hidden" name="neirong" id="inputidnumber" placeholder="max<20位" maxlength="20" /><textarea value="{$xinxianshi['neirong']}" name="neirong" style=" height:100%;" 

                                >{$xinxianshi['neirong']}</textarea><br />
                            </div>
                            <div class="form-group">
                                <label for="inputSubject">是否显示</label>
                                <tr >
                                    <td>&nbsp;&nbsp;&nbsp;&nbsp;<input type="radio" name="xianshi" id="inputSubject"  value="1" >是
                                    </td>
                                    <td>&nbsp;&nbsp;<input type="radio" name="xianshi" id="inputSubject"  value="0"></td>否
                                </tr>
                                <!-- <input type="radio" name="RR" value="1">
                                <input type="radio" name="RR" value="2"> -->
                            </div>
                       

                        </div><!-- /.box-body -->
                        <div class="box-footer clearfix">
                           <!--  <a href="{:U('edit', ['user_id'=>$user['id']])}" class="btn btn-default" title="编辑"><span class="fa fa-edit"></span> 编辑</a> -->
                            <button class="btn btn-primary" type="submit" name="submit" value="publish">更新</button>
                            <!-- <button class="btn btn-info" type="submit" name="submit" value="save">仅保存</button> -->
                        </div><!-- /.box-footer -->
                    </form>

controller：

//start
    /**
     * 编辑前展示xinxianshi
     */
    public function bianjiAction($xinxianshi_id=0)
    {   //s
        
        //e

        // 通用查询条件
        $m_xinxianshi = M('Xinxianshi');
            //匹配xinxianshiid并展示：
                    $condition['id'] = $xinxianshi_id;
                    $m_xinxianshi = D('Xinxianshi');
                    $xinxianshi = $m_xinxianshi
                    ->table('lb_xinxianshi')
                    ->field('lb_xinxianshi.*')
                    ->where($condition)
                    ->find();
                    
                    $this->assign('xinxianshi', $xinxianshi);
                    //echo $m_xinxianshi->getLastSQL();exit;
                    //var_dump($xinxianshi);
            //$this->display();

            //更新    
            // 判断当前是post还是get
        if (IS_POST)
        {
            $m_xinxianshi = D('Xinxianshi');

        
            // 处理提交的数据
            $m_xinxianshi->create(); // 默认去post中获取数据
            $m_xinxianshi->birthday = strtotime($_POST['birthday']);
            $m_xinxianshi->regtime = time();
            $m_xinxianshi->logintimes = time();
                // 数据校验通过
            $m_xinxianshi->save();
                
            // 数据插入或者验证无存在问题
            $this->success('OK：' , U('Xinxianshi/list'), 2);
        }
        else
        {
            // 展示添加表单
            // 把分类分配给表单
            $m_category = D('Category');
            $category_list = $m_category->getTree();
            $this->assign('category_list', $category_list);

            $this->display();
        }
    }
//end

效果：

Paste_Image.png