<script type="text/javascript">

            function onRowDropping(sender, args) {
                if (sender.get_id() == "<%=grdPendingOrders.ClientID %>") {
                    var node = args.get_destinationHtmlElement();
                    if (!isChildOf('<%=grdShippedOrders.ClientID %>', node) && !isChildOf('<%=grdPendingOrders.ClientID %>', node)) {
                        args.set_cancel(true);
                    }

                }
                else if (sender.get_id() == "<%=grdShippedOrders.ClientID %>") {
                    var node = args.get_destinationHtmlElement();
                    if (!isChildOf('<%=grdPendingOrders.ClientID %>', node) && !isChildOf('<%=grdShippedOrders.ClientID %>', node)) {
                        args.set_cancel(true);
                    }
                }

                else {
                    var node = args.get_destinationHtmlElement();
                    if (!isChildOf('trashCan', node)) {
                        args.set_cancel(true);
                    }
                    else {
                        if (confirm("Are you sure you want to delete this order?"))
                            args.set_destinationHtmlElement($get('trashCan'));
                        else
                            args.set_cancel(true);
                    }
                }
            }
            function isChildOf(parentId, element) {
                while (element) {
                    if (element.id && element.id.indexOf(parentId) > -1) {
                        return true;
                    }
                    element = element.parentNode;
                }
                return false;
            }

        </script>