function extendMenu( id ){
	if( $('submenu_' + id ).style.display != "block"){
		$('submenu_' + id ).style.display = 'block';
	}
}

function closeMenu( id ){
	if( $('submenu_' + id ).style.display != "none"){
		$('submenu_' + id ).style.display = 'none';
	}
}