function sichtbar(navlayer)
		{
			
			if(document.layers)
			{
				document.layers[navlayer].visibility = 'show';
				
			}
			else if(document.getElementById)
			{
				document.getElementById(navlayer).style.visibility = 'visible';
				
			}		
		}
		
function nichtsichtbar(navlayer2)
		{
			
			if(document.layers)
			{
			
				document.layers[navlayer2].visibility = 'hide';
			}
			else if(document.getElementById)
			{
				
				document.getElementById(navlayer2).style.visibility = 'hidden';
			}	
			
				
		}