function showlayer(layer){
	var myLayer=document.getElementById(layer).style.display;
	if(myLayer=="none"){
		document.getElementById(layer).style.visibility="hidden";
	} else { 
		document.getElementById(layer).style.visibility="visible";
		}
}
function hidelayer(layer){
	var myLayer=document.getElementById(layer).style.display;
	if(myLayer=="none"){
		document.getElementById(layer).style.visibility="visible";
	} else { 
		document.getElementById(layer).style.visibility="hidden";
		}
}