function hiddenMenu(id){
	obj = document.getElementById(id);
	if(obj.style.display=="none"){
		obj.style.display="block";
	}
	else{
		obj.style.display="none";
	}
	return (obj.style.display=="none");
}
function invertMenu(x1, x2){
	obj1 = document.getElementById(x1);
	obj2 = document.getElementById(x2);
	if(obj1.style.display=="none"){
		obj2.style.display="block";
	}
	else{
		obj2.style.display="none";
	}
}