function ShowHide(listname)
{
	list= document.getElementById(listname);
	switch (list.style.display){
	case "":
	{
	list.style.display = "none"
	}
	break
	case "none":
	{
	list.style.display = ""
	}
	break
	default:
		list.style.display = "none"
	}


}