Выпадающее меню

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; 
      // -->