+=item C<ajax_submit_tag $url, $form_selector, $text, %attributes>
+
+Creates a HTML 'input type="button"' tag with a very specific onclick
+handler that submits the form given by the jQuery selector
+C<$form_selector> to the URL C<$url> (the actual JavaScript function
+called for that is C<kivi.submit_ajax_form()> in
+C<js/client_js.js>). The button's label will be C<$text>.
+