how to refresh form validation and how to serialize data with fileinput?

hello. I have got the form. I was created it with ActiveForm class. I blocked standart submit with preventDefault(); And afterValidate I submit the form with ajax:

$('#form').on('afterValidate', function () {

    var url = $('#form').attr('action');

        var data = $('#form').serialize();


            type: "POST",

            url: url,

            data: data,



All works good. But only first time, second submit is not working with another data. How I can reset validation of the form after every submit for this good form working with ajax, like I want to see?

And one more question about ajax submit. I submitted the form with the same code, but if I using enctype = ‘multipart/form-data’ it’s not working, yii gives error to me:

PHP Fatal Error 'yii\base\ErrorException' with message 'Call to a member function saveAs() on a non-object

How I can serialize the data with fileinput too?

Thank you