function $ (element) 
{
	return document.getElementById(element);
}
function subMenu(sender, id)
{
	if($("sub_menu_"+id).style.display  == "block")
	{
		$("sub_menu_"+id).style.display  = "none"
	}
	else
	{
		$("sub_menu_"+id).style.display  = "block" ;
	};
}