nemmo\attachments\components\AttachmentsInput::init PHP Method

    public function init()
    {
        parent::init();
        // TODO: Change the autogenerated stub
        if (empty($this->model)) {
            throw new InvalidConfigException("Property {model} cannot be blank");
        }
        FileHelper::removeDirectory($this->getModule()->getUserDirPath());
        // Delete all uploaded files in past
        $this->pluginOptions = array_replace($this->pluginOptions, ['uploadUrl' => Url::toRoute('/attachments/file/upload'), 'initialPreview' => $this->model->isNewRecord ? [] : $this->model->getInitialPreview(), 'initialPreviewConfig' => $this->model->isNewRecord ? [] : $this->model->getInitialPreviewConfig(), 'uploadAsync' => false]);
        $this->options = array_replace($this->options, ['id' => $this->id]);
        $js = <<<JS
var fileInput = \$('#file-input');
var form = fileInput.closest('form');
var filesUploaded = false;
var filesToUpload = 0;
var uploadButtonClicked = false;
//var formSubmit = false;
form.on('beforeSubmit', function(event) { // form submit event
    console.log('submit');
    if (!filesUploaded && filesToUpload) {
        console.log('upload');
        \$('#file-input').fileinput('upload').fileinput('lock');

        return false;
    }
});

fileInput.on('filebatchpreupload', function(event, data, previewId, index) {
    uploadButtonClicked = true;
});

//fileInput.on('filebatchuploadcomplete', function(event, files, extra) { // all files successfully uploaded
fileInput.on('filebatchuploadsuccess', function(event, data, previewId, index) {
    filesUploaded = true;
    \$('#file-input').fileinput('unlock');
    if (uploadButtonClicked) {
        form.submit();
    } else {
        uploadButtonClicked = false;
    }
});

fileInput.on('filebatchselected', function(event, files) { // there are some files to upload
    filesToUpload = files.length
});

fileInput.on('filecleared', function(event) { // no files to upload
    filesToUpload = 0;
});

JS;
        \Yii::$app->view->registerJs($js);
    }