从dropzone.js上传图像文件

Question

请帮助您了解如何将选定图像从dropzone上传到特定目录。这是我的代码：

    <div class="dropzone" id="mydropzone">
        <div class="dropzone-previews"></div>
        </div>
        <button type="submit" id="submitbtn">Upload</button>
    </div>
    <script>
            Dropzone.options.mydropzone = {
                url:"upload.php",
                uploadMultiple: true,
                maxFilesize: 2,
                maxFiles : 3,
                autoDiscover:false,
                acceptedFiles: ".png,.jpg,.jpeg",
                previewsContainer: '.dropzone-previews',
                autoProcessQueue : false,
                parallelUploads: 100,
                addRemoveLinks: true,       
                init:function(){
                    var myDropzone = this;
                    $("#submitbtn").on('click',function(e) {
                       e.preventDefault();
                       myDropzone.processQueue();
                    });
                }

           }
</script>

我可以在dropzone中拖动照片，但它不会出现在我的子目录中。这是upload.php上的代码：

session_start();

$ds = DIRECTORY_SEPARATOR;
$upload_dir = './upload_photos';

if (!empty($_FILES)) { 
     $tempFile = $_FILES['file']['tmp_name'];
     $targetPath = dirname(__FILE__).$ds.$upload_dir.$ds;
     $targetFile = $targetPath. $_FILES['file']['name']; 

     move_uploaded_file($tempFile,$targetFile);

}

我该怎么办？