function show_menu(id){
	document.getElementById('menu'+id).style['display'] = 'block';
	document.getElementById('menubtn'+id).style['background'] = 'none';
}

function hide_menu(id){
	document.getElementById('menu'+id).style['display'] = 'none';
	document.getElementById('menubtn'+id).style['background'] = 'url(images/en/m'+id+'.gif) no-repeat top left';
}