具体代码如下：

（推荐教程：yii）

1、model

<?phpnamespace frontend\models; use yii\base\Model;use yii\web\UploadedFile;use yii\db\ActiveRecord;use yii\db\Query; class UploadForm extends ActiveRecord{    /**     * @var UploadedFile     */    public $t_img;    public $t_title;    public $t_content;    public function rules()    {        return [            [['t_img'], 'file', 'skipOnEmpty' => false, 'extensions' => 'png, jpg,bmp,jpeg'],        ];    }    public function attributeLabels()    {        return [            't_img'=>'请上传文章图片',            'verifyCode' => '请在右面输入验证码',        ];    }      public function upload()    {        $imgName=time().rand(100,999).".".$this->t_img->extension;        if ($this->validate()) {            $this->t_img->saveAs('uploads/' .$imgName);            $path='uploads/' .$imgName;            return $path;        } else {            return false;        }    }} ?>

2、控制器

 $data=Yii::$app->request->post();            $data['t_addtime']=date('Y-m-d H:i:s');            $upload->t_img = UploadedFile::getInstance($upload, 't_img');            $path=$upload->upload();

3、视图层

<?phpuse yii\widgets\ActiveForm;use yii\helpers\Html;use yii\helpers\Url;?><?=Html::a('返回','?r=course/classspace&c_id='.$c_id)?><?php $form=ActiveForm::begin(    [        'options' => ['enctype' => 'multipart/form-data'],        'method'=>'POST',    ]);?><table class="table">     <tr>        <td>             <input type="text" placeholder="请填写话题标题" name="t_title" id="t_title" value=<?=$coursedraft['d_title']?>   >        </td>        </tr>    <tr>        <td>            <textarea name="t_content" id="t_content" cols="30" rows="10" placeholder="请填写话题内容"><?=$coursedraft['d_content']?></textarea>        </td>    </tr>    <tr>        <td>           <?=$form->field($upload,'t_img')->fileInput()?>        </td>    </tr>    <tr>        <div class="btn-group">            <td>                <?=Html::submitButton('提交话题',['class'=>'btn btn-success'])?>            </td>        </div>     </tr></table><?php ActiveForm::end();?><input type="hidden" value=<?=$c_id?>  id="c_id" /></body><?php$js = <<<END    $(function(){//        $(document).on('click','#caogao',function() {//            var title = $("#t_title").val();//            var content = $("#t_content").val();////            $.ajax({//                type: "POST",//                url: "?r=course/coursedraft",//                data: {t_title: title, t_content: content, d_id: d_id}//            })//        })        function show(){            var title=$("#t_title").val();            var content=$("#t_content").val();            var c_id=$('#c_id').val();            $.ajax({                type: "POST",                url: "?r=course/coursedraft",                data: {d_title:title,d_content:content,c_id:c_id,d_state:0}            });        }        setInterval(show,5000);    })END;$this->registerJs($js);?></html>