Here is page A.     session storage, HTML syntax

   Push an entry onto the history stack.

       page A          same-page navigation
       page A top
       page A bottom

       page B          cross-page
       page B top
       page B bottom

   Travel back and forth in the stack using the browser’s
   navigation controls.

   Travel direction is reported to the debugging console
   as backward (-1), reload (0) or forward (1).