function toon (keuzemenu,terugmenu) {
				eval ("document"+layerRef+"'"+keuzemenu+"'"+styleRef+".visibility='visible'");
				eval ("document"+layerRef+"'"+terugmenu+"'"+styleRef+".visibility='hidden'");
				}
				
				function writeCookie() 
				{ 
				var today = new Date(); 
				var the_date = new Date("December 31, 2023"); 
				var the_cookie_date = the_date.toGMTString(); 
				var willegen_breedte = "users_resolution="+ screen.width; 
				var willegen_breedte = willegen_breedte + ";expires=" + the_cookie_date; 
				document.cookie = willegen_breedte ;
				} 
				writeCookie(); 

				if (document.layers) { 
				layerRef=".layers[";
				styleRef="]";
				}
				else if (document.all) { 
				layerRef=".all[";
				styleRef="].style";
				}
				else if (document.getElementById) { 
				layerRef=".getElementById(";
				styleRef=").style";
				}
		
				function toon (keuzemenu,terugmenu) {
				eval ("document"+layerRef+"'"+keuzemenu+"'"+styleRef+".visibility='visible'");
				eval ("document"+layerRef+"'"+terugmenu+"'"+styleRef+".visibility='hidden'");
				}