function show_hidden(div_name) {
	div = document.getElementById(div_name);
	if (div)
	{
		if (div.style.display == 'none') show_div(div_name);
		else hide_div(div_name);
	}
}

function hide_div(element_id){
	document.getElementById(element_id).style.display = "none";
}

function show_div(element_id){
	document.getElementById(element_id).style.display = "block";
}

function e(el_id){
	return document.getElementById(el_id);
}


function change_open_cat(el, block_id, class_add){

	if (e(block_id).style.display == 'none'){
		open_cat(el, block_id, class_add)
	} else {
		close_cat(el, block_id, class_add)
	}
}

function open_cat(el, block_id, class_add){
	show_div(block_id);
	el.className += " " + class_add;
}

function close_cat(el, block_id, class_add){
	hide_div(block_id);
	el.className = el.className.replace(" " + class_add, "");
}

function choose_cat(cat_id, class_add, type){
	cat = e(cat_id);
	child_nums=cat.getAttribute('child_nums');
	if (child_nums == null) child_nums = 0;

	if (type){
		if (child_nums == 0){
			cat.className += " " + class_add;
		}
		child_nums++;
	} else {
		child_nums--;
		if (child_nums < 0) child_nums = 0;
		if (child_nums == 0){
			cat.className = cat.className.replace(" " + class_add, "");
		}
	}

	cat.setAttribute('child_nums', child_nums);
}