toggle.html

<button id=hide>Hide boxes</button>
<button id=show>Show boxes</button>

<script>
  var $hide = $("#hide")
  ,   $show = $("#show")
  ,   $els = $("pre.foo")
  ;
  function hide () {
      $els.hide();
      $hide.hide();
      $show.show();
  }
  function show () {
      $els.show();
      $hide.show();
      $show.hide();
  }
  $hide.click(hide);
  $show.click(show);
  // default to show
  show();
</script>