function hideChildren(parent, disable, unset)
{
	if (!parent)
		return;
	
	if (parent.children)
	{
		for (var i = 0; i < parent.children.length; i++)
		{
			if (parent.children[i].children)
				hideChildren(parent.children[i], disable, unset);
		}
	}
	parent.style.display = 'none';
	if (disable)
		parent.disabled = true;
	if (unset && parent.tagName != 'OPTION')
		parent.value = '';
}

function showChildren(parent, disable)
{
	if (!parent)
		return;
	
	if (parent.children)
	{
		for (var i = 0; i < parent.children.length; i++)
		{
			if (parent.children[i].children)
				showChildren(parent.children[i], disable);
		}
	}
	parent.style.display = '';
	if (disable)
		parent.disabled = false;
}