}

        @Override
        public boolean onStartElement(String elementName, Map<String, String> attributes) {
            listener.warning(String.format("Unsupported HTML element <%s>", elementName));
            Element element = document.createElement("UNHANDLED-ELEMENT");
            element.appendChild(document.createTextNode(String.format("<%s>", elementName)));
            nodes.push(element);
            return true;
        }