<form id="ajaxform" enctype="multipart/form-data" class="form">

 <input type="file" class="input-file" accept="image/gif, image/jpeg" id="uploadimg"  name="image[]" multiple />

 <input type="button" id="postbtn" class="input-btn" value="上传" />

 </form> 

 <script src="https://cdn.bootcss.com/jquery/3.3.1/jquery.min.js"></script>

 <script type="text/javascript">

 <!--

     $(function(){

         $("#postbtn").on("click",function(){

             var formData = new FormData($("#ajaxform")[0]);

             console.log(formData);

             $.ajax({

                 type: "POST",

                 data:formData,

                 url:"imgupload",

                 contentType:false,

                 processData:false,

                 success: function(data){

                     console.log(data);

                 }});

             });

     });

 //-->

 </script>

 //图片上传 ROOT_PATH.'uploads'

     public function imgupload(){

         $files = request()->file('image');

         foreach($files as $file){

             // 移动到框架应用根目录/public/uploads/ 目录下

             $info = $file->validate(['size'=>156780,'ext'=>'jpg,png,gif'])->move(ROOT_PATH . 'public' . DS . 'upload');

             if(!$info){

                 // 上传失败获取错误信息

                 echo $file->getError();

             }

         }

     }