/*
    * Copyright (c) 2002-2025 Gargoyle Software Inc.
    *
    * Licensed under the Apache License, Version 2.0 (the "License");
    * you may not use this file except in compliance with the License.
    * You may obtain a copy of the License at
    * https://www.apache.org/licenses/LICENSE-2.0
    *
    * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package org.htmlunit.html;
  
  import static org.htmlunit.BrowserVersionFeatures.EVENT_CONTEXT_MENU_HAS_DETAIL_1;
  import static org.htmlunit.BrowserVersionFeatures.EVENT_ONCLICK_USES_POINTEREVENT;
  import static org.htmlunit.BrowserVersionFeatures.JS_AREA_WITHOUT_HREF_FOCUSABLE;
  
  import java.io.IOException;
  import java.io.PrintWriter;
  import java.io.Serializable;
  import java.io.StringWriter;
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.Collections;
  import java.util.Comparator;
  import java.util.Iterator;
  import java.util.LinkedHashMap;
  import java.util.List;
  import java.util.Locale;
  import java.util.Map;
  import java.util.NoSuchElementException;
  import java.util.Set;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.htmlunit.BrowserVersion;
  import org.htmlunit.Page;
  import org.htmlunit.ScriptResult;
  import org.htmlunit.SgmlPage;
  import org.htmlunit.WebClient;
  import org.htmlunit.css.ComputedCssStyleDeclaration;
  import org.htmlunit.css.CssStyleSheet;
  import org.htmlunit.css.StyleElement;
  import org.htmlunit.cssparser.dom.CSSStyleDeclarationImpl;
  import org.htmlunit.cssparser.dom.Property;
  import org.htmlunit.cssparser.parser.CSSException;
  import org.htmlunit.cssparser.parser.selector.Selector;
  import org.htmlunit.cssparser.parser.selector.SelectorList;
  import org.htmlunit.cssparser.parser.selector.SelectorSpecificity;
  import org.htmlunit.cyberneko.util.FastHashMap;
  import org.htmlunit.html.DefaultElementFactory.OrderedFastHashMapWithLowercaseKeys;
  import org.htmlunit.javascript.AbstractJavaScriptEngine;
  import org.htmlunit.javascript.JavaScriptEngine;
  import org.htmlunit.javascript.host.event.Event;
  import org.htmlunit.javascript.host.event.EventTarget;
  import org.htmlunit.javascript.host.event.MouseEvent;
  import org.htmlunit.javascript.host.event.PointerEvent;
  import org.htmlunit.util.OrderedFastHashMap;
  import org.htmlunit.util.StringUtils;
  import org.w3c.dom.Attr;
  import org.w3c.dom.DOMException;
  import org.w3c.dom.Element;
  import org.w3c.dom.NamedNodeMap;
  import org.w3c.dom.Node;
  import org.w3c.dom.TypeInfo;
  import org.xml.sax.SAXException;
  
  /**
   * @author Ahmed Ashour
   * @author Marc Guillemot
   * @author <a href="mailto:tom.anderson@univ.oxon.org">Tom Anderson</a>
   * @author Ronald Brill
   * @author Frank Danek
   * @author Sven Strickroth
   */
  public class DomElement extends DomNamespaceNode implements Element {
  
      private static final Log LOG = LogFactory.getLog(DomElement.class);
  
      /** id. */
      public static final String ID_ATTRIBUTE = "id";
  
      /** name. */
      public static final String NAME_ATTRIBUTE = "name";
  
      /** src. */
      public static final String SRC_ATTRIBUTE = "src";
  
      /** value. */
      public static final String VALUE_ATTRIBUTE = "value";
  
      /** type. */
      public static final String TYPE_ATTRIBUTE = "type";
  
      /** Constant meaning that the specified attribute was not defined. */
      public static final String ATTRIBUTE_NOT_DEFINED = new String("");
 
     /** Constant meaning that the specified attribute was found but its value was empty. */
     public static final String ATTRIBUTE_VALUE_EMPTY = new String();
 
     /** The map holding the attributes, keyed by name. */
     private NamedAttrNodeMapImpl attributes_;
 
     /** The map holding the namespaces, keyed by URI. */
     private FastHashMap<String, String> namespaces_;
 
     /** Cache for the styles. */
     private String styleString_;
     private LinkedHashMap<String, StyleElement> styleMap_;
 
     private static final Comparator<StyleElement> STYLE_ELEMENT_COMPARATOR = new Comparator<StyleElement>() {
         @Override
         public int compare(final StyleElement first, final StyleElement second) {
             return StyleElement.compareToByImportanceAndSpecificity(first, second);
         }
     };
 
     /**
      * Whether the Mouse is currently over this element or not.
      */
     private boolean mouseOver_;
 
     /**
      * Creates an instance of a DOM element that can have a namespace.
      *
      * @param namespaceURI the URI that identifies an XML namespace
      * @param qualifiedName the qualified name of the element type to instantiate
      * @param page the page that contains this element
      * @param attributes a map ready initialized with the attributes for this element, or
      *        {@code null}. The map will be stored as is, not copied.
      */
     public DomElement(final String namespaceURI, final String qualifiedName, final SgmlPage page,
             final Map<String, DomAttr> attributes) {
         super(namespaceURI, qualifiedName, page);
 
         if (attributes == null) {
             attributes_ = new NamedAttrNodeMapImpl(this, isAttributeCaseSensitive());
         }
         else {
             attributes_ = new NamedAttrNodeMapImpl(this, isAttributeCaseSensitive(), attributes);
 
             for (final DomAttr entry : attributes.values()) {
                 entry.setParentNode(this);
                 final String attrNamespaceURI = entry.getNamespaceURI();
                 final String prefix = entry.getPrefix();
 
                 if (attrNamespaceURI != null && prefix != null) {
                     if (namespaces_ == null) {
                         namespaces_ = new FastHashMap<>(1, 0.5f);
                     }
                     namespaces_.put(attrNamespaceURI, prefix);
                 }
             }
         }
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public String getNodeName() {
         return getQualifiedName();
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public final short getNodeType() {
         return ELEMENT_NODE;
     }
 
     /**
      * Returns the tag name of this element.
      * @return the tag name of this element
      */
     @Override
     public final String getTagName() {
         return getNodeName();
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public final boolean hasAttributes() {
         return !attributes_.isEmpty();
     }
 
     /**
      * Returns whether the attribute specified by name has a value.
      *
      * @param attributeName the name of the attribute
      * @return true if an attribute with the given name is specified on this element or has a
      *        default value, false otherwise.
      */
     @Override
     public boolean hasAttribute(final String attributeName) {
         return attributes_.containsKey(attributeName);
     }
 
     /**
      * <span style="color:red">INTERNAL API - SUBJECT TO CHANGE AT ANY TIME - USE AT YOUR OWN RISK.</span><br>
      *
      * Replaces the value of the named style attribute. If there is no style attribute with the
      * specified name, a new one is added. If the specified value is an empty (or all whitespace)
      * string, this method actually removes the named style attribute.
      * @param name the attribute name (delimiter-separated, not camel-cased)
      * @param value the attribute value
      * @param priority the new priority of the property; <code>"important"</code>or the empty string if none.
      */
     public void replaceStyleAttribute(final String name, final String value, final String priority) {
         if (org.apache.commons.lang3.StringUtils.isBlank(value)) {
             removeStyleAttribute(name);
             return;
         }
 
         final Map<String, StyleElement> styleMap = getStyleMap();
         final StyleElement old = styleMap.get(name);
         final StyleElement element;
         if (old == null) {
             element = new StyleElement(name, value, priority, SelectorSpecificity.FROM_STYLE_ATTRIBUTE);
         }
         else {
             element = new StyleElement(name, value, priority,
                     SelectorSpecificity.FROM_STYLE_ATTRIBUTE, old.getIndex());
         }
         styleMap.put(name, element);
         writeStyleToElement(styleMap);
     }
 
     /**
      * <span style="color:red">INTERNAL API - SUBJECT TO CHANGE AT ANY TIME - USE AT YOUR OWN RISK.</span><br>
      *
      * Removes the specified style attribute, returning the value of the removed attribute.
      * @param name the attribute name (delimiter-separated, not camel-cased)
      * @return the removed value
      */
     public String removeStyleAttribute(final String name) {
         final Map<String, StyleElement> styleMap = getStyleMap();
         final StyleElement value = styleMap.get(name);
         if (value == null) {
             return "";
         }
         styleMap.remove(name);
         writeStyleToElement(styleMap);
         return value.getValue();
     }
 
     /**
      * <span style="color:red">INTERNAL API - SUBJECT TO CHANGE AT ANY TIME - USE AT YOUR OWN RISK.</span><br>
      *
      * Determines the StyleElement for the given name.
      *
      * @param name the name of the requested StyleElement
      * @return the StyleElement or null if not found
      */
     public StyleElement getStyleElement(final String name) {
         final Map<String, StyleElement> map = getStyleMap();
         if (map != null) {
             return map.get(name);
         }
         return null;
     }
 
     /**
      * <span style="color:red">INTERNAL API - SUBJECT TO CHANGE AT ANY TIME - USE AT YOUR OWN RISK.</span><br>
      *
      * Determines the StyleElement for the given name.
      * This ignores the case of the name.
      *
      * @param name the name of the requested StyleElement
      * @return the StyleElement or null if not found
      */
     public StyleElement getStyleElementCaseInSensitive(final String name) {
         final Map<String, StyleElement> map = getStyleMap();
         for (final Map.Entry<String, StyleElement> entry : map.entrySet()) {
             if (entry.getKey().equalsIgnoreCase(name)) {
                 return entry.getValue();
             }
         }
         return null;
     }
 
     /**
      * <span style="color:red">INTERNAL API - SUBJECT TO CHANGE AT ANY TIME - USE AT YOUR OWN RISK.</span><br>
      *
      * Returns a sorted map containing style elements, keyed on style element name. We use a
      * {@link LinkedHashMap} map so that results are deterministic and are thus testable.
      *
      * @return a sorted map containing style elements, keyed on style element name
      */
     public LinkedHashMap<String, StyleElement> getStyleMap() {
         final String styleAttribute = getAttributeDirect("style");
         if (styleString_ == styleAttribute) {
             return styleMap_;
         }
 
         final LinkedHashMap<String, StyleElement> styleMap = new LinkedHashMap<>();
         if (ATTRIBUTE_NOT_DEFINED == styleAttribute || ATTRIBUTE_VALUE_EMPTY == styleAttribute) {
             styleMap_ = styleMap;
             styleString_ = styleAttribute;
             return styleMap_;
         }
 
         final CSSStyleDeclarationImpl cssStyle = new CSSStyleDeclarationImpl(null);
         try {
             // use the configured cssErrorHandler here to do the same error handling during
             // parsing of inline styles like for external css
             cssStyle.setCssText(styleAttribute, getPage().getWebClient().getCssErrorHandler());
         }
         catch (final Exception e) {
             if (LOG.isErrorEnabled()) {
                 LOG.error("Error while parsing style value '" + styleAttribute + "'", e);
             }
         }
 
         for (final Property prop : cssStyle.getProperties()) {
             final String key = prop.getName().toLowerCase(Locale.ROOT);
             final StyleElement element = new StyleElement(key,
                     prop.getValue().getCssText(),
                     prop.isImportant() ? StyleElement.PRIORITY_IMPORTANT : "",
                     SelectorSpecificity.FROM_STYLE_ATTRIBUTE);
             styleMap.put(key, element);
         }
 
         styleMap_ = styleMap;
         styleString_ = styleAttribute;
         // styleString_ = cssStyle.getCssText();
         return styleMap_;
     }
 
     /**
      * Prints the content between "&lt;" and "&gt;" (or "/&gt;") in the output of the tag name
      * and its attributes in XML format.
      * @param printWriter the writer to print in
      */
     protected void printOpeningTagContentAsXml(final PrintWriter printWriter) {
         printWriter.print(getTagName());
         for (final Map.Entry<String, DomAttr> entry : attributes_.entrySet()) {
             printWriter.print(" ");
             printWriter.print(entry.getKey());
             printWriter.print("=\"");
             printWriter.print(StringUtils.escapeXmlAttributeValue(entry.getValue().getNodeValue()));
             printWriter.print("\"");
         }
     }
 
     /**
      * Recursively write the XML data for the node tree starting at <code>node</code>.
      *
      * @param indent white space to indent child nodes
      * @param printWriter writer where child nodes are written
      */
     @Override
     protected void printXml(final String indent, final PrintWriter printWriter) {
         final boolean hasChildren = getFirstChild() != null;
         printWriter.print(indent + "<");
         printOpeningTagContentAsXml(printWriter);
 
         if (hasChildren || isEmptyXmlTagExpanded()) {
             printWriter.print(">\r\n");
             printChildrenAsXml(indent, printWriter);
             printWriter.print(indent);
             printWriter.print("</");
             printWriter.print(getTagName());
             printWriter.print(">\r\n");
         }
         else {
             printWriter.print("/>\r\n");
         }
     }
 
     /**
      * Indicates if a node without children should be written in expanded form as XML
      * (i.e. with closing tag rather than with "/&gt;")
      * @return {@code false} by default
      */
     protected boolean isEmptyXmlTagExpanded() {
         return false;
     }
 
     /**
      * Returns the qualified name (prefix:local) for the specified namespace and local name,
      * or {@code null} if the specified namespace URI does not exist.
      *
      * @param namespaceURI the URI that identifies an XML namespace
      * @param localName the name within the namespace
      * @return the qualified name for the specified namespace and local name
      */
     String getQualifiedName(final String namespaceURI, final String localName) {
         final String qualifiedName;
         if (namespaceURI == null) {
             qualifiedName = localName;
         }
         else {
             final String prefix = namespaces_ == null ? null : namespaces_.get(namespaceURI);
             if (prefix == null) {
                 qualifiedName = null;
             }
             else {
                 qualifiedName = prefix + ':' + localName;
             }
         }
         return qualifiedName;
     }
 
     /**
      * Returns the value of the attribute specified by name or an empty string. If the
      * result is an empty string then it will be either {@link #ATTRIBUTE_NOT_DEFINED}
      * if the attribute wasn't specified or {@link #ATTRIBUTE_VALUE_EMPTY} if the
      * attribute was specified but it was empty.
      *
      * @param attributeName the name of the attribute
      * @return the value of the attribute or {@link #ATTRIBUTE_NOT_DEFINED} or {@link #ATTRIBUTE_VALUE_EMPTY}
      */
     @Override
     public String getAttribute(final String attributeName) {
         final DomAttr attr = attributes_.get(attributeName);
         if (attr != null) {
             return attr.getNodeValue();
         }
         return ATTRIBUTE_NOT_DEFINED;
     }
 
     /**
      * <span style="color:red">INTERNAL API - SUBJECT TO CHANGE AT ANY TIME - USE AT YOUR OWN RISK.</span><br>
      *
      * @param attributeName the name of the attribute
      * @return the value of the attribute or {@link #ATTRIBUTE_NOT_DEFINED} or {@link #ATTRIBUTE_VALUE_EMPTY}
      */
     public String getAttributeDirect(final String attributeName) {
         final DomAttr attr = attributes_.getDirect(attributeName);
         if (attr != null) {
             return attr.getNodeValue();
         }
         return ATTRIBUTE_NOT_DEFINED;
     }
 
     /**
      * Removes an attribute specified by name from this element.
      * @param attributeName the attribute attributeName
      */
     @Override
     public void removeAttribute(final String attributeName) {
         attributes_.remove(attributeName);
     }
 
     /**
      * Removes an attribute specified by namespace and local name from this element.
      * @param namespaceURI the URI that identifies an XML namespace
      * @param localName the name within the namespace
      */
     @Override
     public final void removeAttributeNS(final String namespaceURI, final String localName) {
         final String qualifiedName = getQualifiedName(namespaceURI, localName);
         if (qualifiedName != null) {
             removeAttribute(qualifiedName);
         }
     }
 
     /**
      * {@inheritDoc}
      * Not yet implemented.
      */
     @Override
     public final Attr removeAttributeNode(final Attr attribute) {
         throw new UnsupportedOperationException("DomElement.removeAttributeNode is not yet implemented.");
     }
 
     /**
      * Returns whether the attribute specified by namespace and local name has a value.
      *
      * @param namespaceURI the URI that identifies an XML namespace
      * @param localName the name within the namespace
      * @return true if an attribute with the given name is specified on this element or has a
      *         default value, false otherwise.
      */
     @Override
     public final boolean hasAttributeNS(final String namespaceURI, final String localName) {
         final String qualifiedName = getQualifiedName(namespaceURI, localName);
         if (qualifiedName != null) {
             return attributes_.get(qualifiedName) != null;
         }
         return false;
     }
 
     /**
      * Returns the map holding the attributes, keyed by name.
      * @return the attributes map
      */
     public final Map<String, DomAttr> getAttributesMap() {
         return attributes_;
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public NamedNodeMap getAttributes() {
         return attributes_;
     }
 
     /**
      * Sets the value of the attribute specified by name.
      *
      * @param attributeName the name of the attribute
      * @param attributeValue the value of the attribute
      */
     @Override
     public void setAttribute(final String attributeName, final String attributeValue) {
         setAttributeNS(null, attributeName, attributeValue);
     }
 
     /**
      * Sets the value of the attribute specified by namespace and qualified name.
      *
      * @param namespaceURI the URI that identifies an XML namespace
      * @param qualifiedName the qualified name (prefix:local) of the attribute
      * @param attributeValue the value of the attribute
      */
     @Override
     public void setAttributeNS(final String namespaceURI, final String qualifiedName,
             final String attributeValue) {
         setAttributeNS(namespaceURI, qualifiedName, attributeValue, true, true);
     }
 
     /**
      * Sets the value of the attribute specified by namespace and qualified name.
      *
      * @param namespaceURI the URI that identifies an XML namespace
      * @param qualifiedName the qualified name (prefix:local) of the attribute
      * @param attributeValue the value of the attribute
      * @param notifyAttributeChangeListeners to notify the associated {@link HtmlAttributeChangeListener}s
      * @param notifyMutationObservers to notify {@code MutationObserver}s or not
      */
     protected void setAttributeNS(final String namespaceURI, final String qualifiedName,
             final String attributeValue, final boolean notifyAttributeChangeListeners,
             final boolean notifyMutationObservers) {
         final DomAttr newAttr = new DomAttr(getPage(), namespaceURI, qualifiedName, attributeValue, true);
         newAttr.setParentNode(this);
         attributes_.put(qualifiedName, newAttr);
 
         if (namespaceURI != null) {
             if (namespaces_ == null) {
                 namespaces_ = new FastHashMap<>(1, 0.5f);
             }
             namespaces_.put(namespaceURI, newAttr.getPrefix());
         }
     }
 
     /**
      * Indicates if the attribute names are case sensitive.
      * @return {@code true}
      */
     protected boolean isAttributeCaseSensitive() {
         return true;
     }
 
     /**
      * Returns the value of the attribute specified by namespace and local name or an empty
      * string. If the result is an empty string then it will be either {@link #ATTRIBUTE_NOT_DEFINED}
      * if the attribute wasn't specified or {@link #ATTRIBUTE_VALUE_EMPTY} if the
      * attribute was specified but it was empty.
      *
      * @param namespaceURI the URI that identifies an XML namespace
      * @param localName the name within the namespace
      * @return the value of the attribute or {@link #ATTRIBUTE_NOT_DEFINED} or {@link #ATTRIBUTE_VALUE_EMPTY}
      */
     @Override
     public final String getAttributeNS(final String namespaceURI, final String localName) {
         final String qualifiedName = getQualifiedName(namespaceURI, localName);
         if (qualifiedName != null) {
             return getAttribute(qualifiedName);
         }
         return ATTRIBUTE_NOT_DEFINED;
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public DomAttr getAttributeNode(final String name) {
         return attributes_.get(name);
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public DomAttr getAttributeNodeNS(final String namespaceURI, final String localName) {
         final String qualifiedName = getQualifiedName(namespaceURI, localName);
         if (qualifiedName != null) {
             return attributes_.get(qualifiedName);
         }
         return null;
     }
 
     /**
      * <span style="color:red">INTERNAL API - SUBJECT TO CHANGE AT ANY TIME - USE AT YOUR OWN RISK.</span><br>
      *
      * @param styleMap the styles
      */
     public void writeStyleToElement(final Map<String, StyleElement> styleMap) {
         if (styleMap.isEmpty()) {
             setAttribute("style", "");
             return;
         }
 
         final StringBuilder builder = new StringBuilder();
         final List<StyleElement> styleElements = new ArrayList<>(styleMap.values());
         Collections.sort(styleElements, STYLE_ELEMENT_COMPARATOR);
         for (final StyleElement e : styleElements) {
             if (builder.length() != 0) {
                 builder.append(' ');
             }
             builder.append(e.getName())
                 .append(": ")
                 .append(e.getValue());
 
             final String prio = e.getPriority();
             if (org.apache.commons.lang3.StringUtils.isNotBlank(prio)) {
                 builder.append(" !").append(prio);
             }
             builder.append(';');
         }
         setAttribute("style", builder.toString());
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public DomNodeList<HtmlElement> getElementsByTagName(final String tagName) {
         return getElementsByTagNameImpl(tagName);
     }
 
     /**
      * This should be {@link #getElementsByTagName(String)}, but is separate because of the type erasure in Java.
      * @param tagName The name of the tag to match on
      * @return A list of matching elements.
      */
     <E extends HtmlElement> DomNodeList<E> getElementsByTagNameImpl(final String tagName) {
         return new AbstractDomNodeList<E>(this) {
             @Override
             @SuppressWarnings("unchecked")
             protected List<E> provideElements() {
                 final List<E> res = new ArrayList<>();
                 for (final HtmlElement elem : getDomNode().getHtmlElementDescendants()) {
                     if (elem.getLocalName().equalsIgnoreCase(tagName)) {
                         res.add((E) elem);
                     }
                 }
                 return res;
             }
         };
     }
 
     /**
      * <span style="color:red">INTERNAL API - SUBJECT TO CHANGE AT ANY TIME - USE AT YOUR OWN RISK.</span><br>
      *
      * @param <E> the specific HtmlElement type
      * @param tagName The name of the tag to match on
      * @return A list of matching elements; this is not a live list
      */
     public <E extends HtmlElement> List<E> getStaticElementsByTagName(final String tagName) {
         final List<E> res = new ArrayList<>();
         for (final Iterator<HtmlElement> iterator = this.new DescendantHtmlElementsIterator(); iterator.hasNext();) {
             final HtmlElement elem = iterator.next();
             if (elem.getLocalName().equalsIgnoreCase(tagName)) {
                 final String prefix = elem.getPrefix();
                 if (prefix == null || prefix.isEmpty()) {
                     res.add((E) elem);
                 }
             }
         }
         return res;
     }
 
     /**
      * {@inheritDoc}
      * Not yet implemented.
      */
     @Override
     public DomNodeList<HtmlElement> getElementsByTagNameNS(final String namespace, final String localName) {
         throw new UnsupportedOperationException("DomElement.getElementsByTagNameNS is not yet implemented.");
     }
 
     /**
      * {@inheritDoc}
      * Not yet implemented.
      */
     @Override
     public TypeInfo getSchemaTypeInfo() {
         throw new UnsupportedOperationException("DomElement.getSchemaTypeInfo is not yet implemented.");
     }
 
     /**
      * {@inheritDoc}
      * Not yet implemented.
      */
     @Override
     public void setIdAttribute(final String name, final boolean isId) {
         throw new UnsupportedOperationException("DomElement.setIdAttribute is not yet implemented.");
     }
 
     /**
      * {@inheritDoc}
      * Not yet implemented.
      */
     @Override
     public void setIdAttributeNS(final String namespaceURI, final String localName, final boolean isId) {
         throw new UnsupportedOperationException("DomElement.setIdAttributeNS is not yet implemented.");
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public Attr setAttributeNode(final Attr attribute) {
         attributes_.setNamedItem(attribute);
         return null;
     }
 
     /**
      * {@inheritDoc}
      * Not yet implemented.
      */
     @Override
     public Attr setAttributeNodeNS(final Attr attribute) {
         throw new UnsupportedOperationException("DomElement.setAttributeNodeNS is not yet implemented.");
     }
 
     /**
      * {@inheritDoc}
      * Not yet implemented.
      */
     @Override
     public final void setIdAttributeNode(final Attr idAttr, final boolean isId) {
         throw new UnsupportedOperationException("DomElement.setIdAttributeNode is not yet implemented.");
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public DomNode cloneNode(final boolean deep) {
         final DomElement clone = (DomElement) super.cloneNode(deep);
         clone.attributes_ = new NamedAttrNodeMapImpl(clone, isAttributeCaseSensitive());
         clone.attributes_.putAll(attributes_);
         return clone;
     }
 
     /**
      * @return the identifier of this element
      */
     public final String getId() {
         return getAttributeDirect(ID_ATTRIBUTE);
     }
 
     /**
      * Sets the identifier this element.
      *
      * @param newId the new identifier of this element
      */
     public final void setId(final String newId) {
         setAttribute(ID_ATTRIBUTE, newId);
     }
 
     /**
      * Returns the first child element node of this element. null if this element has no child elements.
      * @return the first child element node of this element. null if this element has no child elements
      */
     public DomElement getFirstElementChild() {
         final Iterator<DomElement> i = getChildElements().iterator();
         if (i.hasNext()) {
             return i.next();
         }
         return null;
     }
 
     /**
      * Returns the last child element node of this element. null if this element has no child elements.
      * @return the last child element node of this element. null if this element has no child elements
      */
     public DomElement getLastElementChild() {
         DomElement lastChild = null;
         for (final DomElement domElement : getChildElements()) {
             lastChild = domElement;
         }
         return lastChild;
     }
 
     /**
      * Returns the current number of element nodes that are children of this element.
      * @return the current number of element nodes that are children of this element.
      */
     public int getChildElementCount() {
         int counter = 0;
 
         final Iterator<DomElement> iterator = getChildElements().iterator();
         while (iterator.hasNext()) {
             iterator.next();
             counter++;
         }
         return counter;
     }
 
     /**
      * @return an Iterable over the DomElement children of this object, i.e. excluding the non-element nodes
      */
     public final Iterable<DomElement> getChildElements() {
         return new ChildElementsIterable(this);
     }
 
     /**
      * An Iterable over the DomElement children.
      */
     private static class ChildElementsIterable implements Iterable<DomElement> {
         private final Iterator<DomElement> iterator_;
 
         /**
          * Constructor.
          * @param domNode the parent
          */
         protected ChildElementsIterable(final DomNode domNode) {
             iterator_ = new ChildElementsIterator(domNode);
         }
 
         @Override
         public Iterator<DomElement> iterator() {
             return iterator_;
         }
     }
 
     /**
      * An iterator over the DomElement children.
      */
     protected static class ChildElementsIterator implements Iterator<DomElement> {
 
         private DomElement nextElement_;
 
         /**
          * Constructor.
          * @param domNode the parent
          */
         protected ChildElementsIterator(final DomNode domNode) {
             final DomNode child = domNode.getFirstChild();
             if (child != null) {
                 if (child instanceof DomElement) {
                     nextElement_ = (DomElement) child;
                 }
                 else {
                     setNextElement(child);
                 }
             }
         }
 
         /**
          * @return is there a next one ?
          */
         @Override
         public boolean hasNext() {
             return nextElement_ != null;
         }
 
         /**
          * @return the next one
          */
         @Override
         public DomElement next() {
             if (nextElement_ != null) {
                 final DomElement result = nextElement_;
                 setNextElement(nextElement_);
                 return result;
             }
             throw new NoSuchElementException();
         }
 
         /** Removes the current one. */
         @Override
         public void remove() {
             if (nextElement_ == null) {
                 throw new IllegalStateException();
             }
             final DomNode sibling = nextElement_.getPreviousSibling();
             if (sibling != null) {
                 sibling.remove();
             }
         }
 
         private void setNextElement(final DomNode node) {
             DomNode next = node.getNextSibling();
             while (next != null && !(next instanceof DomElement)) {
                 next = next.getNextSibling();
             }
             nextElement_ = (DomElement) next;
         }
     }
 
     /**
      * Returns a string representation of this element.
      * @return a string representation of this element
      */
     @Override
     public String toString() {
         final StringWriter writer = new StringWriter();
         final PrintWriter printWriter = new PrintWriter(writer);
 
         printWriter.print(getClass().getSimpleName());
         printWriter.print("[<");
         printOpeningTagContentAsXml(printWriter);
         printWriter.print(">]");
         printWriter.flush();
         return writer.toString();
     }
 
     /**
      * Simulates clicking on this element, returning the page in the window that has the focus
      * after the element has been clicked. Note that the returned page may or may not be the same
      * as the original page, depending on the type of element being clicked, the presence of JavaScript
      * action listeners, etc.<br>
      * This only clicks the element if it is visible and enabled (isDisplayed() &amp; !isDisabled()).
      * In case the element is not visible and/or disabled, only a log output is generated.
      * <br>
      * If you circumvent the visible/disabled check use click(shiftKey, ctrlKey, altKey, true, true, false)
      *
      * @param <P> the page type
      * @return the page contained in the current window as returned by {@link WebClient#getCurrentWindow()}
      * @exception IOException if an IO error occurs
      */
     public <P extends Page> P click() throws IOException {
         return click(false, false, false);
     }
 
     /**
      * Simulates clicking on this element, returning the page in the window that has the focus
      * after the element has been clicked. Note that the returned page may or may not be the same
      * as the original page, depending on the type of element being clicked, the presence of JavaScript
      * action listeners, etc.<br>
      * This only clicks the element if it is visible and enabled (isDisplayed() &amp; !isDisabled()).
      * In case the element is not visible and/or disabled, only a log output is generated.
      * <br>
      * If you circumvent the visible/disabled check use click(shiftKey, ctrlKey, altKey, true, true, false)
      *
      * @param shiftKey {@code true} if SHIFT is pressed during the click
      * @param ctrlKey {@code true} if CTRL is pressed during the click
      * @param altKey {@code true} if ALT is pressed during the click
      * @param <P> the page type
      * @return the page contained in the current window as returned by {@link WebClient#getCurrentWindow()}
      * @exception IOException if an IO error occurs
      */
     public <P extends Page> P click(final boolean shiftKey, final boolean ctrlKey, final boolean altKey)
         throws IOException {
 
         return click(shiftKey, ctrlKey, altKey, true);
     }
 
     /**
      * Simulates clicking on this element, returning the page in the window that has the focus
      * after the element has been clicked. Note that the returned page may or may not be the same
      * as the original page, depending on the type of element being clicked, the presence of JavaScript
      * action listeners, etc.<br>
      * This only clicks the element if it is visible and enabled (isDisplayed() &amp; !isDisabled()).
      * In case the element is not visible and/or disabled, only a log output is generated.
      * <br>
      * If you circumvent the visible/disabled check use click(shiftKey, ctrlKey, altKey, true, true, false)
      *
      * @param shiftKey {@code true} if SHIFT is pressed during the click
      * @param ctrlKey {@code true} if CTRL is pressed during the click
      * @param altKey {@code true} if ALT is pressed during the click
      * @param triggerMouseEvents if true trigger the mouse events also
      * @param <P> the page type
      * @return the page contained in the current window as returned by {@link WebClient#getCurrentWindow()}
      * @exception IOException if an IO error occurs
      */
     public <P extends Page> P click(final boolean shiftKey, final boolean ctrlKey, final boolean altKey,
             final boolean triggerMouseEvents) throws IOException {
         return click(shiftKey, ctrlKey, altKey, triggerMouseEvents, true, false, false);
     }
 
     /**
      * @return true if this is an {@link DisabledElement} and disabled
      */
     protected boolean isDisabledElementAndDisabled() {
         return this instanceof DisabledElement && ((DisabledElement) this).isDisabled();
     }
 
     /**
      * <span style="color:red">INTERNAL API - SUBJECT TO CHANGE AT ANY TIME - USE AT YOUR OWN RISK.</span><br>
      *
      * Simulates clicking on this element, returning the page in the window that has the focus
      * after the element has been clicked. Note that the returned page may or may not be the same
      * as the original page, depending on the type of element being clicked, the presence of JavaScript
      * action listeners, etc.
      *
      * @param shiftKey {@code true} if SHIFT is pressed during the click
      * @param ctrlKey {@code true} if CTRL is pressed during the click
      * @param altKey {@code true} if ALT is pressed during the click
      * @param triggerMouseEvents if true trigger the mouse events also
      * @param handleFocus if true set the focus (and trigger the event)
      * @param ignoreVisibility whether to ignore visibility or not
      * @param disableProcessLabelAfterBubbling ignore label processing
      * @param <P> the page type
      * @return the page contained in the current window as returned by {@link WebClient#getCurrentWindow()}
      * @exception IOException if an IO error occurs
      */
     @SuppressWarnings("unchecked")
     public <P extends Page> P click(final boolean shiftKey, final boolean ctrlKey, final boolean altKey,
             final boolean triggerMouseEvents, final boolean handleFocus, final boolean ignoreVisibility,
             final boolean disableProcessLabelAfterBubbling) throws IOException {
 
         // make enclosing window the current one
         final SgmlPage page = getPage();
         final WebClient webClient = page.getWebClient();
         webClient.setCurrentWindow(page.getEnclosingWindow());
 
         if (!ignoreVisibility) {
             if (!(page instanceof HtmlPage)) {
                 return (P) page;
             }
 
             if (!isDisplayed()) {
                 if (LOG.isWarnEnabled()) {
                     LOG.warn("Calling click() ignored because the target element '" + this
                                     + "' is not displayed.");
                 }
                 return (P) page;
             }
 
             if (isDisabledElementAndDisabled()) {
                 if (LOG.isWarnEnabled()) {
                     LOG.warn("Calling click() ignored because the target element '" + this + "' is disabled.");
                 }
                 return (P) page;
             }
         }
 
         synchronized (page) {
             if (triggerMouseEvents) {
                 mouseDown(shiftKey, ctrlKey, altKey, MouseEvent.BUTTON_LEFT);
             }
 
             final AbstractJavaScriptEngine<?> jsEngine = webClient.getJavaScriptEngine();
             if (webClient.isJavaScriptEnabled()) {
                 jsEngine.holdPosponedActions();
             }
             try {
                 if (handleFocus) {
                     // give focus to current element (if possible) or only remove it from previous one
                     DomElement elementToFocus = null;
                     if (this instanceof SubmittableElement
                         || this instanceof HtmlAnchor
                             && ATTRIBUTE_NOT_DEFINED != ((HtmlAnchor) this).getHrefAttribute()
                         || this instanceof HtmlArea
                             && (ATTRIBUTE_NOT_DEFINED != ((HtmlArea) this).getHrefAttribute()
                                 || webClient.getBrowserVersion().hasFeature(JS_AREA_WITHOUT_HREF_FOCUSABLE))
                         || this instanceof HtmlElement && ((HtmlElement) this).getTabIndex() != null) {
                         elementToFocus = this;
                     }
                     else if (this instanceof HtmlOption) {
                         elementToFocus = ((HtmlOption) this).getEnclosingSelect();
                     }
 
                     if (elementToFocus == null) {
                         ((HtmlPage) page).setFocusedElement(null);
                     }
                     else {
                         elementToFocus.focus();
                     }
                 }
 
                 if (triggerMouseEvents) {
                     mouseUp(shiftKey, ctrlKey, altKey, MouseEvent.BUTTON_LEFT);
                 }
 
                 MouseEvent event = null;
                 if (webClient.isJavaScriptEnabled()) {
                     final BrowserVersion browser = webClient.getBrowserVersion();
                     if (browser.hasFeature(EVENT_ONCLICK_USES_POINTEREVENT)) {
                         event = new PointerEvent(getEventTargetElement(), MouseEvent.TYPE_CLICK, shiftKey,
                                 ctrlKey, altKey, MouseEvent.BUTTON_LEFT, 1);
                     }
                     else {
                         event = new MouseEvent(getEventTargetElement(), MouseEvent.TYPE_CLICK, shiftKey,
                                 ctrlKey, altKey, MouseEvent.BUTTON_LEFT, 1);
                     }
 
                     if (disableProcessLabelAfterBubbling) {
                         event.disableProcessLabelAfterBubbling();
                     }
                 }
                 click(event, shiftKey, ctrlKey, altKey, ignoreVisibility);
             }
             finally {
                 if (webClient.isJavaScriptEnabled()) {
                     jsEngine.processPostponedActions();
                 }
             }
 
             return (P) webClient.getCurrentWindow().getEnclosedPage();
         }
     }
 
     /**
      * Returns the event target element. This could be overridden by subclasses to have other targets.
      * The default implementation returns 'this'.
      * @return the event target element.
      */
     protected DomNode getEventTargetElement() {
         return this;
     }
 
     /**
      * <span style="color:red">INTERNAL API - SUBJECT TO CHANGE AT ANY TIME - USE AT YOUR OWN RISK.</span><br>
      *
      * Simulates clicking on this element, returning the page in the window that has the focus
      * after the element has been clicked. Note that the returned page may or may not be the same
      * as the original page, depending on the type of element being clicked, the presence of JavaScript
      * action listeners, etc.
      *
      * @param event the click event used
      * @param shiftKey {@code true} if SHIFT is pressed during the click
      * @param ctrlKey {@code true} if CTRL is pressed during the click
      * @param altKey {@code true} if ALT is pressed during the click
      * @param ignoreVisibility whether to ignore visibility or not
      * @param <P> the page type
      * @return the page contained in the current window as returned by {@link WebClient#getCurrentWindow()}
      * @exception IOException if an IO error occurs
      */
     @SuppressWarnings("unchecked")
     public <P extends Page> P click(final Event event,
                         final boolean shiftKey, final boolean ctrlKey, final boolean altKey,
                         final boolean ignoreVisibility) throws IOException {
         final SgmlPage page = getPage();
 
         if ((!ignoreVisibility && !isDisplayed()) || isDisabledElementAndDisabled()) {
             return (P) page;
         }
 
         final WebClient webClient = page.getWebClient();
         if (!webClient.isJavaScriptEnabled()) {
             doClickStateUpdate(shiftKey, ctrlKey);
 
             webClient.loadDownloadedResponses();
             return (P) getPage().getWebClient().getCurrentWindow().getEnclosedPage();
         }
 
         // may be different from page when working with "orphaned pages"
         // (ex: clicking a link in a page that is not active anymore)
         final Page contentPage = page.getEnclosingWindow().getEnclosedPage();
 
         boolean stateUpdated = false;
         boolean changed = false;
         if (isStateUpdateFirst()) {
             changed = doClickStateUpdate(shiftKey, ctrlKey);
             stateUpdated = true;
         }
 
         final ScriptResult scriptResult = doClickFireClickEvent(event);
         final boolean eventIsAborted = event.isAborted(scriptResult);
 
         final boolean pageAlreadyChanged = contentPage != page.getEnclosingWindow().getEnclosedPage();
         if (!pageAlreadyChanged && !stateUpdated && !eventIsAborted) {
             changed = doClickStateUpdate(shiftKey, ctrlKey);
         }
 
         if (changed) {
             doClickFireChangeEvent();
         }
 
         webClient.loadDownloadedResponses();
         return (P) getPage().getWebClient().getCurrentWindow().getEnclosedPage();
     }
 
     /**
      * This method implements the control state update part of the click action.
      *
      * <p>The default implementation only calls doClickStateUpdate on parent's DomElement (if any).
      * Subclasses requiring different behavior (like {@link HtmlSubmitInput}) will override this method.</p>
      * @param shiftKey {@code true} if SHIFT is pressed
      * @param ctrlKey {@code true} if CTRL is pressed
      *
      * @return true if doClickFireEvent method has to be called later on (to signal,
      *         that the value was changed)
      * @throws IOException if an IO error occurs
      */
     protected boolean doClickStateUpdate(final boolean shiftKey, final boolean ctrlKey) throws IOException {
         if (propagateClickStateUpdateToParent()) {
             // needed for instance to perform link doClickAction when a nested element is clicked
             // it should probably be changed to do this at the event level but currently
             // this wouldn't work with JS disabled as events are propagated in the host object tree.
             final DomNode parent = getParentNode();
             if (parent instanceof DomElement) {
                 return ((DomElement) parent).doClickStateUpdate(false, false);
             }
         }
 
         return false;
     }
 
     /**
      * Usually the click is propagated to the parent. Overwrite if you like to disable this.
      * @return true or false
      * @see #doClickStateUpdate(boolean, boolean)
      */
     protected boolean propagateClickStateUpdateToParent() {
         return true;
     }
 
     /**
      * This method implements the control onchange handler call during the click action.
      */
     protected void doClickFireChangeEvent() {
         // nothing to do, in the default case
     }
 
     /**
      * This method implements the control onclick handler call during the click action.
      * @param event the click event used
      * @return the script result
      */
     protected ScriptResult doClickFireClickEvent(final Event event) {
         return fireEvent(event);
     }
 
     /**
      * Simulates double-clicking on this element, returning the page in the window that has the focus
      * after the element has been clicked. Note that the returned page may or may not be the same
      * as the original page, depending on the type of element being clicked, the presence of JavaScript
      * action listeners, etc. Note also that {@link #click()} is automatically called first.
      *
      * @param <P> the page type
      * @return the page that occupies this element's window after the element has been double-clicked
      * @exception IOException if an IO error occurs
      */
     public <P extends Page> P dblClick() throws IOException {
         return dblClick(false, false, false);
     }
 
     /**
      * Simulates double-clicking on this element, returning the page in the window that has the focus
      * after the element has been clicked. Note that the returned page may or may not be the same
      * as the original page, depending on the type of element being clicked, the presence of JavaScript
      * action listeners, etc. Note also that {@link #click(boolean, boolean, boolean)} is automatically
      * called first.
      *
      * @param shiftKey {@code true} if SHIFT is pressed during the double-click
      * @param ctrlKey {@code true} if CTRL is pressed during the double-click
      * @param altKey {@code true} if ALT is pressed during the double-click
      * @param <P> the page type
      * @return the page that occupies this element's window after the element has been double-clicked
      * @exception IOException if an IO error occurs
      */
     @SuppressWarnings("unchecked")
     public <P extends Page> P dblClick(final boolean shiftKey, final boolean ctrlKey, final boolean altKey)
         throws IOException {
         if (isDisabledElementAndDisabled()) {
             return (P) getPage();
         }
 
         // call click event first
         P clickPage = click(shiftKey, ctrlKey, altKey);
         if (clickPage != getPage()) {
             LOG.debug("dblClick() is ignored, as click() loaded a different page.");
             return clickPage;
         }
 
         // call click event a second time
         clickPage = click(shiftKey, ctrlKey, altKey);
         if (clickPage != getPage()) {
             LOG.debug("dblClick() is ignored, as click() loaded a different page.");
             return clickPage;
         }
 
         final Event event;
         event = new MouseEvent(this, MouseEvent.TYPE_DBL_CLICK, shiftKey, ctrlKey, altKey,
                 MouseEvent.BUTTON_LEFT, 2);
 
         final ScriptResult scriptResult = fireEvent(event);
         if (scriptResult == null) {
             return clickPage;
         }
         return (P) getPage().getWebClient().getCurrentWindow().getEnclosedPage();
     }
 
     /**
      * Simulates moving the mouse over this element, returning the page which this element's window contains
      * after the mouse move. The returned page may or may not be the same as the original page, depending
      * on JavaScript event handlers, etc.
      *
      * @return the page which this element's window contains after the mouse move
      */
     public Page mouseOver() {
         return mouseOver(false, false, false, MouseEvent.BUTTON_LEFT);
     }
 
     /**
      * Simulates moving the mouse over this element, returning the page which this element's window contains
      * after the mouse move. The returned page may or may not be the same as the original page, depending
      * on JavaScript event handlers, etc.
      *
      * @param shiftKey {@code true} if SHIFT is pressed during the mouse move
      * @param ctrlKey {@code true} if CTRL is pressed during the mouse move
      * @param altKey {@code true} if ALT is pressed during the mouse move
      * @param button the button code, must be {@link MouseEvent#BUTTON_LEFT}, {@link MouseEvent#BUTTON_MIDDLE}
      *        or {@link MouseEvent#BUTTON_RIGHT}
      * @return the page which this element's window contains after the mouse move
      */
     public Page mouseOver(final boolean shiftKey, final boolean ctrlKey, final boolean altKey, final int button) {
         return doMouseEvent(MouseEvent.TYPE_MOUSE_OVER, shiftKey, ctrlKey, altKey, button);
     }
 
     /**
      * Simulates moving the mouse over this element, returning the page which this element's window contains
      * after the mouse move. The returned page may or may not be the same as the original page, depending
      * on JavaScript event handlers, etc.
      *
      * @return the page which this element's window contains after the mouse move
      */
     public Page mouseMove() {
         return mouseMove(false, false, false, MouseEvent.BUTTON_LEFT);
     }
 
     /**
      * Simulates moving the mouse over this element, returning the page which this element's window contains
      * after the mouse move. The returned page may or may not be the same as the original page, depending
      * on JavaScript event handlers, etc.
      *
      * @param shiftKey {@code true} if SHIFT is pressed during the mouse move
      * @param ctrlKey {@code true} if CTRL is pressed during the mouse move
      * @param altKey {@code true} if ALT is pressed during the mouse move
      * @param button the button code, must be {@link MouseEvent#BUTTON_LEFT}, {@link MouseEvent#BUTTON_MIDDLE}
      *        or {@link MouseEvent#BUTTON_RIGHT}
      * @return the page which this element's window contains after the mouse move
      */
     public Page mouseMove(final boolean shiftKey, final boolean ctrlKey, final boolean altKey, final int button) {
         return doMouseEvent(MouseEvent.TYPE_MOUSE_MOVE, shiftKey, ctrlKey, altKey, button);
     }
 
     /**
      * Simulates moving the mouse out of this element, returning the page which this element's window contains
      * after the mouse move. The returned page may or may not be the same as the original page, depending
      * on JavaScript event handlers, etc.
      *
      * @return the page which this element's window contains after the mouse move
      */
     public Page mouseOut() {
         return mouseOut(false, false, false, MouseEvent.BUTTON_LEFT);
     }
 
     /**
      * Simulates moving the mouse out of this element, returning the page which this element's window contains
      * after the mouse move. The returned page may or may not be the same as the original page, depending
      * on JavaScript event handlers, etc.
      *
      * @param shiftKey {@code true} if SHIFT is pressed during the mouse move
      * @param ctrlKey {@code true} if CTRL is pressed during the mouse move
      * @param altKey {@code true} if ALT is pressed during the mouse move
      * @param button the button code, must be {@link MouseEvent#BUTTON_LEFT}, {@link MouseEvent#BUTTON_MIDDLE}
      *        or {@link MouseEvent#BUTTON_RIGHT}
      * @return the page which this element's window contains after the mouse move
      */
     public Page mouseOut(final boolean shiftKey, final boolean ctrlKey, final boolean altKey, final int button) {
         return doMouseEvent(MouseEvent.TYPE_MOUSE_OUT, shiftKey, ctrlKey, altKey, button);
     }
 
     /**
      * Simulates clicking the mouse on this element, returning the page which this element's window contains
      * after the mouse click. The returned page may or may not be the same as the original page, depending
      * on JavaScript event handlers, etc.
      *
      * @return the page which this element's window contains after the mouse click
      */
     public Page mouseDown() {
         return mouseDown(false, false, false, MouseEvent.BUTTON_LEFT);
     }
 
     /**
      * Simulates clicking the mouse on this element, returning the page which this element's window contains
      * after the mouse click. The returned page may or may not be the same as the original page, depending
      * on JavaScript event handlers, etc.
      *
      * @param shiftKey {@code true} if SHIFT is pressed during the mouse click
      * @param ctrlKey {@code true} if CTRL is pressed during the mouse click
      * @param altKey {@code true} if ALT is pressed during the mouse click
      * @param button the button code, must be {@link MouseEvent#BUTTON_LEFT}, {@link MouseEvent#BUTTON_MIDDLE}
      *        or {@link MouseEvent#BUTTON_RIGHT}
      * @return the page which this element's window contains after the mouse click
      */
     public Page mouseDown(final boolean shiftKey, final boolean ctrlKey, final boolean altKey, final int button) {
         return doMouseEvent(MouseEvent.TYPE_MOUSE_DOWN, shiftKey, ctrlKey, altKey, button);
     }
 
     /**
      * Simulates releasing the mouse click on this element, returning the page which this element's window contains
      * after the mouse click release. The returned page may or may not be the same as the original page, depending
      * on JavaScript event handlers, etc.
      *
      * @return the page which this element's window contains after the mouse click release
      */
     public Page mouseUp() {
         return mouseUp(false, false, false, MouseEvent.BUTTON_LEFT);
     }
 
     /**
      * Simulates releasing the mouse click on this element, returning the page which this element's window contains
      * after the mouse click release. The returned page may or may not be the same as the original page, depending
      * on JavaScript event handlers, etc.
      *
      * @param shiftKey {@code true} if SHIFT is pressed during the mouse click release
      * @param ctrlKey {@code true} if CTRL is pressed during the mouse click release
      * @param altKey {@code true} if ALT is pressed during the mouse click release
      * @param button the button code, must be {@link MouseEvent#BUTTON_LEFT}, {@link MouseEvent#BUTTON_MIDDLE}
      *        or {@link MouseEvent#BUTTON_RIGHT}
      * @return the page which this element's window contains after the mouse click release
      */
     public Page mouseUp(final boolean shiftKey, final boolean ctrlKey, final boolean altKey, final int button) {
         return doMouseEvent(MouseEvent.TYPE_MOUSE_UP, shiftKey, ctrlKey, altKey, button);
     }
 
     /**
      * Simulates right clicking the mouse on this element, returning the page which this element's window
      * contains after the mouse click. The returned page may or may not be the same as the original page,
      * depending on JavaScript event handlers, etc.
      *
      * @return the page which this element's window contains after the mouse click
      */
     public Page rightClick() {
         return rightClick(false, false, false);
     }
 
     /**
      * Simulates right clicking the mouse on this element, returning the page which this element's window
      * contains after the mouse click. The returned page may or may not be the same as the original page,
      * depending on JavaScript event handlers, etc.
      *
      * @param shiftKey {@code true} if SHIFT is pressed during the mouse click
      * @param ctrlKey {@code true} if CTRL is pressed during the mouse click
      * @param altKey {@code true} if ALT is pressed during the mouse click
      * @return the page which this element's window contains after the mouse click
      */
     public Page rightClick(final boolean shiftKey, final boolean ctrlKey, final boolean altKey) {
         final Page mouseDownPage = mouseDown(shiftKey, ctrlKey, altKey, MouseEvent.BUTTON_RIGHT);
         if (mouseDownPage != getPage()) {
             LOG.debug("rightClick() is incomplete, as mouseDown() loaded a different page.");
             return mouseDownPage;
         }
 
         final Page mouseUpPage = mouseUp(shiftKey, ctrlKey, altKey, MouseEvent.BUTTON_RIGHT);
         if (mouseUpPage != getPage()) {
             LOG.debug("rightClick() is incomplete, as mouseUp() loaded a different page.");
             return mouseUpPage;
         }
 
         return doMouseEvent(MouseEvent.TYPE_CONTEXT_MENU, shiftKey, ctrlKey, altKey, MouseEvent.BUTTON_RIGHT);
     }
 
     /**
      * Simulates the specified mouse event, returning the page which this element's window contains after the event.
      * The returned page may or may not be the same as the original page, depending on JavaScript event handlers, etc.
      *
      * @param eventType the mouse event type to simulate
      * @param shiftKey {@code true} if SHIFT is pressed during the mouse event
      * @param ctrlKey {@code true} if CTRL is pressed during the mouse event
      * @param altKey {@code true} if ALT is pressed during the mouse event
      * @param button the button code, must be {@link MouseEvent#BUTTON_LEFT}, {@link MouseEvent#BUTTON_MIDDLE}
      *        or {@link MouseEvent#BUTTON_RIGHT}
      * @return the page which this element's window contains after the event
      */
     private Page doMouseEvent(final String eventType, final boolean shiftKey, final boolean ctrlKey,
         final boolean altKey, final int button) {
         final SgmlPage page = getPage();
         final WebClient webClient = getPage().getWebClient();
         if (!webClient.isJavaScriptEnabled()) {
             return page;
         }
 
         final ScriptResult scriptResult;
         final Event event;
         if (MouseEvent.TYPE_CONTEXT_MENU.equals(eventType)) {
             final BrowserVersion browserVersion = webClient.getBrowserVersion();
             if (browserVersion.hasFeature(EVENT_ONCLICK_USES_POINTEREVENT)) {
                 if (browserVersion.hasFeature(EVENT_CONTEXT_MENU_HAS_DETAIL_1)) {
                     event = new PointerEvent(this, eventType, shiftKey, ctrlKey, altKey, button, 1);
                 }
                 else {
                     event = new PointerEvent(this, eventType, shiftKey, ctrlKey, altKey, button, 0);
                 }
             }
             else {
                 event = new MouseEvent(this, eventType, shiftKey, ctrlKey, altKey, button, 1);
             }
         }
         else if (MouseEvent.TYPE_DBL_CLICK.equals(eventType)) {
             event = new MouseEvent(this, eventType, shiftKey, ctrlKey, altKey, button, 2);
         }
         else {
             event = new MouseEvent(this, eventType, shiftKey, ctrlKey, altKey, button, 1);
         }
         scriptResult = fireEvent(event);
 
         final Page currentPage;
         if (scriptResult == null) {
             currentPage = page;
         }
         else {
             currentPage = webClient.getCurrentWindow().getEnclosedPage();
         }
 
         final boolean mouseOver = !MouseEvent.TYPE_MOUSE_OUT.equals(eventType);
         if (mouseOver_ != mouseOver) {
             mouseOver_ = mouseOver;
 
             page.clearComputedStyles();
         }
 
         return currentPage;
     }
 
     /**
      * <span style="color:red">INTERNAL API - SUBJECT TO CHANGE AT ANY TIME - USE AT YOUR OWN RISK.</span><br>
      *
      * Shortcut for {@link #fireEvent(Event)}.
      * @param eventType the event type (like "load", "click")
      * @return the execution result, or {@code null} if nothing is executed
      */
     public ScriptResult fireEvent(final String eventType) {
         if (getPage().getWebClient().isJavaScriptEnabled()) {
             return fireEvent(new Event(this, eventType));
         }
         return null;
     }
 
     /**
      * <span style="color:red">INTERNAL API - SUBJECT TO CHANGE AT ANY TIME - USE AT YOUR OWN RISK.</span><br>
      *
      * Fires the event on the element. Nothing is done if JavaScript is disabled.
      * @param event the event to fire
      * @return the execution result, or {@code null} if nothing is executed
      */
     public ScriptResult fireEvent(final Event event) {
         final WebClient client = getPage().getWebClient();
         if (!client.isJavaScriptEnabled()) {
             return null;
         }
 
         if (!handles(event)) {
             return null;
         }
 
         if (LOG.isDebugEnabled()) {
             LOG.debug("Firing " + event);
         }
 
         final EventTarget jsElt = getScriptableObject();
         final ScriptResult result = ((JavaScriptEngine) client.getJavaScriptEngine())
                                         .callSecured(cx -> jsElt.fireEvent(event), getHtmlPageOrNull());
         if (event.isAborted(result)) {
             preventDefault();
         }
         return result;
     }
 
     /**
      * This method is called if the current fired event is canceled by <code>preventDefault()</code>.
      *
      * <p>The default implementation does nothing.</p>
      */
     protected void preventDefault() {
         // Empty by default; override as needed.
     }
 
     /**
      * Sets the focus on this element.
      */
     public void focus() {
         if (!(this instanceof SubmittableElement
             || this instanceof HtmlAnchor && ATTRIBUTE_NOT_DEFINED != ((HtmlAnchor) this).getHrefAttribute()
             || this instanceof HtmlArea
                 && (ATTRIBUTE_NOT_DEFINED != ((HtmlArea) this).getHrefAttribute()
                     || getPage().getWebClient().getBrowserVersion().hasFeature(JS_AREA_WITHOUT_HREF_FOCUSABLE))
             || this instanceof HtmlElement && ((HtmlElement) this).getTabIndex() != null)) {
             return;
         }
 
         if (!isDisplayed() || isDisabledElementAndDisabled()) {
             return;
         }
 
         final HtmlPage page = (HtmlPage) getPage();
         page.setFocusedElement(this);
     }
 
     /**
      * Removes focus from this element.
      */
     public void blur() {
         final HtmlPage page = (HtmlPage) getPage();
         if (page.getFocusedElement() != this) {
             return;
         }
 
         page.setFocusedElement(null);
     }
 
     /**
      * <span style="color:red">INTERNAL API - SUBJECT TO CHANGE AT ANY TIME - USE AT YOUR OWN RISK.</span><br>
      *
      * Gets notified that it has lost the focus.
      */
     public void removeFocus() {
         // nothing
     }
 
     /**
      * Returns {@code true} if state updates should be done before onclick event handling. This method
      * returns {@code false} by default, and is expected to be overridden to return {@code true} by
      * derived classes like {@link HtmlCheckBoxInput}.
      * @return {@code true} if state updates should be done before onclick event handling
      */
     protected boolean isStateUpdateFirst() {
         return false;
     }
 
     /**
      * Returns whether the Mouse is currently over this element or not.
      * @return whether the Mouse is currently over this element or not
      */
     public boolean isMouseOver() {
         if (mouseOver_) {
             return true;
         }
         for (final DomElement child : getChildElements()) {
             if (child.isMouseOver()) {
                 return true;
             }
         }
         return false;
     }
 
     /**
      * Returns true if the element would be selected by the specified selector string; otherwise, returns false.
      * @param selectorString the selector to test
      * @return true if the element would be selected by the specified selector string; otherwise, returns false.
      */
     public boolean matches(final String selectorString) {
         try {
             final WebClient webClient = getPage().getWebClient();
             final SelectorList selectorList = getSelectorList(selectorString, webClient);
 
             if (selectorList != null) {
                 for (final Selector selector : selectorList) {
                     if (CssStyleSheet.selects(webClient.getBrowserVersion(), selector, this, null, true, true)) {
                         return true;
                     }
                 }
             }
             return false;
         }
         catch (final IOException e) {
             throw new CSSException("Error parsing CSS selectors from '" + selectorString + "': " + e.getMessage(), e);
         }
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public void setNodeValue(final String value) {
         // Default behavior is to do nothing, overridden in some subclasses
     }
 
     /**
      * Callback method which allows different HTML element types to perform custom
      * initialization of computed styles. For example, body elements in most browsers
      * have default values for their margins.
      *
      * @param style the style to initialize
      */
     public void setDefaults(final ComputedCssStyleDeclaration style) {
         // Empty by default; override as necessary.
     }
 
     /**
      * Replaces all child elements of this element with the supplied value parsed as html.
      * @param source the new value for the contents of this element
      * @throws SAXException in case of error
      * @throws IOException in case of error
      */
     public void setInnerHtml(final String source) throws SAXException, IOException {
         removeAllChildren();
         getPage().clearComputedStylesUpToRoot(this);
 
         if (source != null) {
             parseHtmlSnippet(source);
         }
     }
 }
 
 /**
  * The {@link NamedNodeMap} to store the node attributes.
  */
 class NamedAttrNodeMapImpl implements Map<String, DomAttr>, NamedNodeMap, Serializable {
     private final OrderedFastHashMap<String, DomAttr> map_;
     private final DomElement domNode_;
     private final boolean caseSensitive_;
 
     NamedAttrNodeMapImpl(final DomElement domNode, final boolean caseSensitive) {
         super();
         if (domNode == null) {
             throw new IllegalArgumentException("Provided domNode can't be null.");
         }
         domNode_ = domNode;
         caseSensitive_ = caseSensitive;
         map_ = new OrderedFastHashMap<>(0);
     }
 
     NamedAttrNodeMapImpl(final DomElement domNode, final boolean caseSensitive,
             final Map<String, DomAttr> attributes) {
         super();
         if (domNode == null) {
             throw new IllegalArgumentException("Provided domNode can't be null.");
         }
         domNode_ = domNode;
         caseSensitive_ = caseSensitive;
 
         if (attributes instanceof OrderedFastHashMapWithLowercaseKeys) {
             // no need to rework the map at all, we are case sensitive, so
             // we keep all attributes and we got the right map from outside too
             map_ = (OrderedFastHashMap) attributes;
         }
         else if (caseSensitive && attributes instanceof OrderedFastHashMap) {
             // no need to rework the map at all, we are case sensitive, so
             // we keep all attributes and we got the right map from outside too
             map_ = (OrderedFastHashMap) attributes;
         }
         else {
             // this is more expensive but atypical, so we don't have to care that much
             map_ = new OrderedFastHashMap<>(attributes.size());
             // this will create a new map with all case lowercased and
             putAll(attributes);
         }
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public int getLength() {
         return size();
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public DomAttr getNamedItem(final String name) {
         return get(name);
     }
 
     private String fixName(final String name) {
         if (caseSensitive_) {
             return name;
         }
         return StringUtils.toRootLowerCase(name);
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public Node getNamedItemNS(final String namespaceURI, final String localName) {
         if (domNode_ == null) {
             return null;
         }
         return get(domNode_.getQualifiedName(namespaceURI, fixName(localName)));
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public Node item(final int index) {
         if (index < 0 || index >= map_.size()) {
             return null;
         }
         return map_.getValue(index);
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public Node removeNamedItem(final String name) throws DOMException {
         return remove(name);
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public Node removeNamedItemNS(final String namespaceURI, final String localName) {
         if (domNode_ == null) {
             return null;
         }
         return remove(domNode_.getQualifiedName(namespaceURI, fixName(localName)));
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public DomAttr setNamedItem(final Node node) {
         return put(node.getLocalName(), (DomAttr) node);
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public Node setNamedItemNS(final Node node) throws DOMException {
         return put(node.getNodeName(), (DomAttr) node);
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public DomAttr put(final String key, final DomAttr value) {
         final String name = fixName(key);
         return map_.put(name, value);
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public DomAttr remove(final Object key) {
         if (key instanceof String) {
             final String name = fixName((String) key);
             return map_.remove(name);
         }
         return null;
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public void clear() {
         map_.clear();
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public void putAll(final Map<? extends String, ? extends DomAttr> t) {
         // add one after the other to save the positions
         for (final Map.Entry<? extends String, ? extends DomAttr> entry : t.entrySet()) {
             put(entry.getKey(), entry.getValue());
         }
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public boolean containsKey(final Object key) {
         if (key instanceof String) {
             final String name = fixName((String) key);
             return map_.containsKey(name);
         }
         return false;
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public DomAttr get(final Object key) {
         if (key instanceof String) {
             final String name = fixName((String) key);
             return map_.get(name);
         }
         return null;
     }
 
     /**
      * Fast access.
      * @param key the key
      */
     protected DomAttr getDirect(final String key) {
         return map_.get(key);
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public boolean containsValue(final Object value) {
         return map_.containsValue(value);
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public Set<Map.Entry<String, DomAttr>> entrySet() {
         return map_.entrySet();
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public boolean isEmpty() {
         return map_.isEmpty();
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public Set<String> keySet() {
         return map_.keySet();
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public int size() {
         return map_.size();
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public Collection<DomAttr> values() {
         return map_.values();
     }
 }