function handleLinkMouseOver(link){
    link.style['textDecoration']='underline';
    link.style['color']='#fefd9a';
  }
  
  function handleLinkMouseOut(link){
    link.style['textDecoration']='none';
    link.style['color']='#ffffff';
  }
  
  var timeout = 500;
  var closetimer  = 0;
  var ddmenuitem  = 0;

  // open hidden layer
  function mopen(id)
  { 
    // cancel close timer
    mcancelclosetime();

    // close old layer
    if(ddmenuitem) ddmenuitem.style.visibility = 'hidden';

    // get new layer and show it
    ddmenuitem = document.getElementById(id);
    ddmenuitem.style.visibility = 'visible';

  }
  // close showed layer
  function mclose()
  {
    if(ddmenuitem) ddmenuitem.style.visibility = 'hidden';
  }

  // go close timer
  function mclosetime()
  {
    closetimer = window.setTimeout(mclose, timeout);
  }

  // cancel close timer
  function mcancelclosetime()
  {
    if(closetimer)
    {
      window.clearTimeout(closetimer);
      closetimer = null;
    }
  }

  // close layer when click-out
  document.onclick = mclose;