function toggle_cat(id) {
	var elem = document.getElementById('cat' + id);
	var childs = document.getElementById('childs' + id);
	if (elem.className == 'open') {
		elem.className = 'closed';
		childs.style.display = 'none';
	} else {
		elem.className = 'open';
		childs.style.display = '';
	}
}

function collapse_menu(except) {
	var uls = document.getElementsByTagName('ul');
	for (i = 0; i < uls.length; ++i) if (uls[i].className == 'childs') uls[i].style.display = 'none';
	var lis = document.getElementsByTagName('li');
	for (i = 0; i < lis.length; ++i) if (lis[i].className == 'open') lis[i].className = 'closed';
	if (except) toggle_cat(except);
}