function auf_zu(wgid)
{
	var start_node = document.getElementById(wgid);						
	if(typeof start_node == "object")
	{
		if(start_node.style.display != "none")
		{
			start_node.style.display = "none";
		}
		else
		{
			start_node.style.display = "block";
		}
	}
}