function get_Object (idx)
{ return document.getElementById(idx); }

function menu_enter (idx)
{ get_Object('menu' + idx).style.visibility = 'visible'; 
  get_Object('th' + idx).style.background = '#4a4a4a';
  get_Object('th' + idx).style.color = '#FF9900';
}

function menu_hide (idx)
{ get_Object('menu'+idx).style.visibility = 'hidden';
  get_Object('th' + idx).style.background = 'transparent';
  get_Object('th' + idx).style.color = '#FF9900';
}

function th_enter (thobject)
{ thobject.style.background = '#4a4a4a';
}

function th_hide (thobject)
{ thobject.style.background = 'transparent';
}