function hideshow(menu_name) {
var menu_names = document.getElementById(menu_name);

if (menu_names.style.visibility == "hidden")
 	{
 	menu_names.style.visibility = "visible";
	menu_names.style.position = "relative";
 	menu_names.style.display="block";
 	}
 
else if (menu_names.style.visibility == "visible")
	{
	menu_names.style.visibility  = "hidden";
	menu_names.style.display = "none";
	menu_names.style.position = "absolute";
	}
}