function change_display(node_id){
	node = document.getElementById(node_id);
	if (node.style.display === 'block') {
		node.style.display = 'none';
	}
	else {
		node.style.display = 'block';
	}
}
function switch_display(node_id){
	node = document.getElementById(node_id);
	var childrens = node.parentNode.getElementsByTagName('DIV');
	for (var i = 0; i < childrens.length; i++) {
		if (childrens[i].id.substr(0, 5) === 'list_') {
			childrens[i].style.display = 'none';
		}
	}

	node.style.display = 'block';
}