On Thu, Mar 20, 2014 at 9:43 AM, Hans Hübner <hans.huebner@gmail.com> wrote:
>  I am not sure whether the functionality is working all that well

It works fine.  Here's an app that is used by my students almost every day:

  http://weitz.de/mars/

Click on the link above and look at the source code.  You should see
that the <FORM ACTION ...> part is properly rewritten.