var NvLayer;
	var NvOldLayer;
	var SegmentWidth;
	var Controll;


	Event.observe(window, 'load', start_pagenv, false);

	function start_pagenv(evt) {
	  Event.observe('mainnavigation', 'mouseover', NvTreeOpen, false);
	  Event.observe(document, 'mousemove', CloseLayer);
	}
	
	function NvTreeOpen(evt){
			
		var child = Event.element(evt);

		if(child.nodeName=='A') {
			
		child = child.ancestors()[2];	
		
			if(NvLayer = child.getElementsByTagName('dl')[0]) {
				
				$('nvViewer').style.display = 'block';
				
				var pos = Position.cumulativeOffset(child);
				
				$('nvViewer').style.left = pos[0]+"px";
				$('nvViewer').style.top = (pos[1])+"px";
				$('nvViewer').innerHTML = child.innerHTML;
					
				if(SegmentWidth = child.getElementsByTagName('a')[0].getWidth()) {
					if($('nvViewer').getElementsByTagName('span')[0]) {
						$('nvViewer').getElementsByTagName('span')[0].style.width = (SegmentWidth+10)  + "px";
					}
					if($('nvViewer').getElementsByTagName('p')[0]) {
						$('nvViewer').getElementsByTagName('p')[0].style.width = (SegmentWidth+10)  + "px";
					}
				}
				
			}
		
		}
			
		Event.stop(evt); //avoid another call related to 'parent_node' itself
		

	}
	
	  function CloseLayer(evt)
      {
		 
		 if($('nvViewer').innerHTML!='' && $('nvViewer').style.display != 'none') {
			 
		
			var pos = Position.cumulativeOffset($('nvViewer'));
			var hight = $('nvViewer').getHeight();
			var width = $('nvViewer').getWidth();
			
			var left = pos[0];
			var top = pos[1];
			var mleft = left + width;
			var mtop = top + hight;

			 if((Event.pointerX(evt) < left || Event.pointerX(evt) > mleft) || (Event.pointerY(evt) < top || Event.pointerY(evt) > mtop))  {			 
				 $('nvViewer').style.display = 'none';
			 }
			 
		 }
		  

      }