Can you use basic FAPI without drupal_build_form? is there any way to use simple FAPI (such as dropdown selection box) without processing it with drupal_build_form?

The thing is, I have a page with a custom table view and a drop-down selection widget that limits the view. The only thing that I need the selection widget to do is to redirect me to '...the_page/id_of_selected_item' (or 'the_page?gid=id_of_selected_item). And it seems to me that using full form support for such a simple task (which a basic redirect surely is) is a bit of a overkill... 

I know I can render the selection widget easily without the form support but then neither AJAX nor simple submit button (that would send the data trough PHP POST) works.

BTW: Is there any way to do simple PHP forms in Drupal?
From https://api.drupal.org/api/drupal/includes%21form.inc/function/drupal_get_form/7.x :


  This function should be used instead of drupal_build_form() when $form_state is not needed (i.e., when initially rendering the form) and is often used as a menu callback.


It still does a drupal_build_form under the hood, though, but at least you don't have to do it. Mind you, it may or may not work in your specific case, depending on where / how you create and call your form.