app.js

$(function () {
    $('#my_form').on('submit', function (e) {
        // prevent browser from submitting the form
        e.preventDefault();
 
        var $form = $(this);
        var formdata = (window.FormData) ? new FormData($form[0]) : null;
        var data = (formdata !== null) ? formdata : $form.serialize();
 
        $.ajax({
            url: $form.attr('action'),
            type: $form.attr('method'),
            contentType: false, // mandatory for the upload
            processData: false, // mandatory for the upload
            dataType: 'json', 
            data: data,
            success: function (response) {
               // server responce
            }
        });
    });
});