I would like to create a url button that redirects to the original location the record was opened from

As per http://www.quickbase.com/developer/articles/using-zrurl-and-rdr-formula-url-fields  "&z=" & Rurl() does not work for a=API_EditRecord. Also I may be mistaken but it seems that even if it did work it would bring me back to the same record I was on when pressing the button. In my case I want it to return me to the previous page, the one I was on before opening the record - as if I pressed save and close