function menuhide(menunum)
  {
    var currentmenu = document.getElementById("bod" + menunum);
    currentmenu.style.visibility = 'hidden';
  }

  function menushow(menunum)
  {
    var currentmenu = document.getElementById("bod" + menunum);
    currentmenu.style.display = 'block';
  }


  function menuinv(menunum)
  {
   var currentmenu = document.getElementById("bod" + menunum);
    if (currentmenu.style.display==='block')
    {
    currentmenu.style.display = 'none';
    }
    else
    {
    currentmenu.style.display = 'block';
    }
    return false;
  }

  function chaptinv(menunum)
  {
   var currentmenu = document.getElementById("chapt" + menunum);
    if (currentmenu.style.display==='block')
    {
    currentmenu.style.display = 'none';
    }
    else
    {
    currentmenu.style.display = 'block';
    }

  }