function s_h(id) {
	p_cat = document.getElementById('cat_' + id);
	p_link = document.getElementById('link_' + id);
	
	if (p_cat.style.display == 'none') {
		p_cat.style.display = 'block';
		p_link.innerHTML = '[-]';
	} else {
		p_cat.style.display = 'none';
		p_link.innerHTML = '[+]';
	}
}