drupal 7 prevent redirect in modal window (ctools) when submit

I have placed a form (built with entityform) into a modal (ctools modal) using jquery.

Now, what happens is that when I click on the "submit" button, I get redirected to another page where I display the "success" message.

I'd like to avoid the redirect and display the "success" message within the modal (in the same page where the modal pop up).

Thanks in advance.

This is the jquery I used to launch the modal on click:

    (function ($) {
        Drupal.behaviors.tuo = {

    attach: function (context, settings) {
        $('#comments_button', context).click(function () {

        $('#suggerimenti').dialog('open');

        $('.ui-dialog-titlebar').append($('h2', '#block-views-invio-suggerimenti-block'));

        $('.ui-dialog-content').append($('form', '#block-views-invio-suggerimenti-block'));

    });

        $('#suggerimenti').dialog({
                autoOpen:false,
                minWidth:500,       
    });
}

}; })(jQuery);

And this is the html of the form created by Drupal:

<form id="prova-invio-entityform-edit-form" class="entityform entitytype-prova_invio-form" accept-charset="UTF-8" method="post" action="/tuo_tema_dev2/?q=content/blandit-ratis-usitas-valde">

    <div>

        <div class="pre-intructions"></div>

        <div id="edit-field-suggerimento-new" class="field-type-text-long field-name-field-suggerimento-new field-widget-text-textarea form-wrapper">

        <div id="edit-field-refer" class="field-type-entityreference field-name-field-refer field-widget-entityreference-autocomplete form-wrapper">

        <div id="edit-actions--3" class="form-actions form-wrapper">

            <input id="edit-submit--4" class="form-submit ajax-processed" type="submit" value="invia suggerimento" name="op">

        </div>

    </div>

</form>

You can add a hidden form value to your form when using the modal view (check if your ajax is set in the URL). Then in your submit function remove your redirect when the form value is present. Assuming it is set using $form_state using this line:

unset($form_state['redirect']);

We can give you more help if you attach your form code. That seems more relevant to me, for this problem, than your JavaScript.