function menu_show(menu_id)
{
  menu_hide();
  window.document.getElementById("s" + menu_id).className = "s-shown";
  window.document.getElementById("a" + menu_id).className = "s-shown";
}


function menu_hide()
{
  window.document.getElementById("s1").className = "s-hidden";
  window.document.getElementById("a1").className = "s-hidden";
  window.document.getElementById("s2").className = "s-hidden";
  window.document.getElementById("a2").className = "s-hidden";
  window.document.getElementById("s3").className = "s-hidden";
  window.document.getElementById("a3").className = "s-hidden";
  window.document.getElementById("s5").className = "s-hidden";
  window.document.getElementById("a5").className = "s-hidden";
}