Form API : $form['the_text_field']['#attributes']['class'][] = 'ctools-auto-submit-exclude';
OR '#attributes' => array('class' => array('ctools-auto-submit-exclude')),
Form API : $form['the_text_field']['#attributes']['class'][] = 'ctools-auto-submit-exclude';
OR '#attributes' => array('class' => array('ctools-auto-submit-exclude')),