function change_menu_open(obj) {
	if( ! obj.id || obj.id.substr(0,7) != 'opener_')	return false;
	
	var search = /_(.*)_/;
	var result = search.exec(obj.id);
	if( ! result )	return false;
	
	var obj_general_id = result[1];
	
	var container_obj = $(obj_general_id +"_container");
	if( ! container_obj)	return false;
	
	var opener_img_obj = $("opener_"+ obj_general_id +"_img");
	if( ! opener_img_obj)	return false;

	if(container_obj.style.display != 'block') {
		container_obj.style.display = 'block';
		opener_img_obj.src = "/img/pfeil_up.gif";
	} else {
		container_obj.style.display = 'none';
		opener_img_obj.src = "/img/pfeil_down.gif";
	}
}