var timeout = 200;
  var closetimer = 0;
  var ddmenuitem = 0;
  var mDynURL='';
  var mURL='';
  // 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;