function invertNode(nodeID, imgIcon) {
            var node = document.getElementById(nodeID);
            if (node) {
                //alert(node.style.display);
                if (node.style.display != "none") {
                    node.style.display = "none";
                    if (imgIcon && imgIcon.src) {
                        imgIcon.src = "images/icons/treeclosed.gif";
                    }
                }
                else {
                    node.style.display = "block";
                    if (imgIcon && imgIcon.src) {
                        imgIcon.src = "images/icons/treeopen.gif";
                    }
                }
            }
        }