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From: aharui@apache.org
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Date: Fri, 25 Sep 2015 04:48:59 -0000
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Subject: [30/83] [abbrv] [partial] git commit: [flex-falcon]
 [refs/heads/develop] - Added GCL extern.

http://git-wip-us.apache.org/repos/asf/flex-falcon/blob/e2cad6e6/externs/GCL/externs/goog/dom/dom.js
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diff --git a/externs/GCL/externs/goog/dom/dom.js b/externs/GCL/externs/goog/dom/dom.js
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+// Copyright 2006 The Closure Library Authors. All Rights Reserved.
+//
+// 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
+//
+//      http://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.
+
+/**
+ * @fileoverview Utilities for manipulating the browser's Document Object Model
+ * Inspiration taken *heavily* from mochikit (http://mochikit.com/).
+ *
+ * You can use {@link goog.dom.DomHelper} to create new dom helpers that refer
+ * to a different document object.  This is useful if you are working with
+ * frames or multiple windows.
+ *
+ * @author arv@google.com (Erik Arvidsson)
+ */
+
+
+// TODO(arv): Rename/refactor getTextContent and getRawTextContent. The problem
+// is that getTextContent should mimic the DOM3 textContent. We should add a
+// getInnerText (or getText) which tries to return the visible text, innerText.
+
+
+goog.provide('goog.dom');
+goog.provide('goog.dom.Appendable');
+goog.provide('goog.dom.DomHelper');
+
+goog.require('goog.array');
+goog.require('goog.asserts');
+goog.require('goog.dom.BrowserFeature');
+goog.require('goog.dom.NodeType');
+goog.require('goog.dom.TagName');
+goog.require('goog.dom.safe');
+goog.require('goog.html.SafeHtml');
+goog.require('goog.math.Coordinate');
+goog.require('goog.math.Size');
+goog.require('goog.object');
+goog.require('goog.string');
+goog.require('goog.string.Unicode');
+goog.require('goog.userAgent');
+
+
+/**
+ * @define {boolean} Whether we know at compile time that the browser is in
+ * quirks mode.
+ */
+goog.define('goog.dom.ASSUME_QUIRKS_MODE', false);
+
+
+/**
+ * @define {boolean} Whether we know at compile time that the browser is in
+ * standards compliance mode.
+ */
+goog.define('goog.dom.ASSUME_STANDARDS_MODE', false);
+
+
+/**
+ * Whether we know the compatibility mode at compile time.
+ * @type {boolean}
+ * @private
+ */
+goog.dom.COMPAT_MODE_KNOWN_ =
+    goog.dom.ASSUME_QUIRKS_MODE || goog.dom.ASSUME_STANDARDS_MODE;
+
+
+/**
+ * Gets the DomHelper object for the document where the element resides.
+ * @param {(Node|Window)=} opt_element If present, gets the DomHelper for this
+ *     element.
+ * @return {!goog.dom.DomHelper} The DomHelper.
+ */
+goog.dom.getDomHelper = function(opt_element) {
+  return opt_element ?
+      new goog.dom.DomHelper(goog.dom.getOwnerDocument(opt_element)) :
+      (goog.dom.defaultDomHelper_ ||
+          (goog.dom.defaultDomHelper_ = new goog.dom.DomHelper()));
+};
+
+
+/**
+ * Cached default DOM helper.
+ * @type {goog.dom.DomHelper}
+ * @private
+ */
+goog.dom.defaultDomHelper_;
+
+
+/**
+ * Gets the document object being used by the dom library.
+ * @return {!Document} Document object.
+ */
+goog.dom.getDocument = function() {
+  return document;
+};
+
+
+/**
+ * Gets an element from the current document by element id.
+ *
+ * If an Element is passed in, it is returned.
+ *
+ * @param {string|Element} element Element ID or a DOM node.
+ * @return {Element} The element with the given ID, or the node passed in.
+ */
+goog.dom.getElement = function(element) {
+  return goog.dom.getElementHelper_(document, element);
+};
+
+
+/**
+ * Gets an element by id from the given document (if present).
+ * If an element is given, it is returned.
+ * @param {!Document} doc
+ * @param {string|Element} element Element ID or a DOM node.
+ * @return {Element} The resulting element.
+ * @private
+ */
+goog.dom.getElementHelper_ = function(doc, element) {
+  return goog.isString(element) ?
+      doc.getElementById(element) :
+      element;
+};
+
+
+/**
+ * Gets an element by id, asserting that the element is found.
+ *
+ * This is used when an element is expected to exist, and should fail with
+ * an assertion error if it does not (if assertions are enabled).
+ *
+ * @param {string} id Element ID.
+ * @return {!Element} The element with the given ID, if it exists.
+ */
+goog.dom.getRequiredElement = function(id) {
+  return goog.dom.getRequiredElementHelper_(document, id);
+};
+
+
+/**
+ * Helper function for getRequiredElementHelper functions, both static and
+ * on DomHelper.  Asserts the element with the given id exists.
+ * @param {!Document} doc
+ * @param {string} id
+ * @return {!Element} The element with the given ID, if it exists.
+ * @private
+ */
+goog.dom.getRequiredElementHelper_ = function(doc, id) {
+  // To prevent users passing in Elements as is permitted in getElement().
+  goog.asserts.assertString(id);
+  var element = goog.dom.getElementHelper_(doc, id);
+  element = goog.asserts.assertElement(element,
+      'No element found with id: ' + id);
+  return element;
+};
+
+
+/**
+ * Alias for getElement.
+ * @param {string|Element} element Element ID or a DOM node.
+ * @return {Element} The element with the given ID, or the node passed in.
+ * @deprecated Use {@link goog.dom.getElement} instead.
+ */
+goog.dom.$ = goog.dom.getElement;
+
+
+/**
+ * Looks up elements by both tag and class name, using browser native functions
+ * ({@code querySelectorAll}, {@code getElementsByTagName} or
+ * {@code getElementsByClassName}) where possible. This function
+ * is a useful, if limited, way of collecting a list of DOM elements
+ * with certain characteristics.  {@code goog.dom.query} offers a
+ * more powerful and general solution which allows matching on CSS3
+ * selector expressions, but at increased cost in code size. If all you
+ * need is particular tags belonging to a single class, this function
+ * is fast and sleek.
+ *
+ * Note that tag names are case sensitive in the SVG namespace, and this
+ * function converts opt_tag to uppercase for comparisons. For queries in the
+ * SVG namespace you should use querySelector or querySelectorAll instead.
+ * https://bugzilla.mozilla.org/show_bug.cgi?id=963870
+ * https://bugs.webkit.org/show_bug.cgi?id=83438
+ *
+ * @see {goog.dom.query}
+ *
+ * @param {?string=} opt_tag Element tag name.
+ * @param {?string=} opt_class Optional class name.
+ * @param {(Document|Element)=} opt_el Optional element to look in.
+ * @return { {length: number} } Array-like list of elements (only a length
+ *     property and numerical indices are guaranteed to exist).
+ */
+goog.dom.getElementsByTagNameAndClass = function(opt_tag, opt_class, opt_el) {
+  return goog.dom.getElementsByTagNameAndClass_(document, opt_tag, opt_class,
+                                                opt_el);
+};
+
+
+/**
+ * Returns a static, array-like list of the elements with the provided
+ * className.
+ * @see {goog.dom.query}
+ * @param {string} className the name of the class to look for.
+ * @param {(Document|Element)=} opt_el Optional element to look in.
+ * @return { {length: number} } The items found with the class name provided.
+ */
+goog.dom.getElementsByClass = function(className, opt_el) {
+  var parent = opt_el || document;
+  if (goog.dom.canUseQuerySelector_(parent)) {
+    return parent.querySelectorAll('.' + className);
+  }
+  return goog.dom.getElementsByTagNameAndClass_(
+      document, '*', className, opt_el);
+};
+
+
+/**
+ * Returns the first element with the provided className.
+ * @see {goog.dom.query}
+ * @param {string} className the name of the class to look for.
+ * @param {Element|Document=} opt_el Optional element to look in.
+ * @return {Element} The first item with the class name provided.
+ */
+goog.dom.getElementByClass = function(className, opt_el) {
+  var parent = opt_el || document;
+  var retVal = null;
+  if (parent.getElementsByClassName) {
+    retVal = parent.getElementsByClassName(className)[0];
+  } else if (goog.dom.canUseQuerySelector_(parent)) {
+    retVal = parent.querySelector('.' + className);
+  } else {
+    retVal = goog.dom.getElementsByTagNameAndClass_(
+        document, '*', className, opt_el)[0];
+  }
+  return retVal || null;
+};
+
+
+/**
+ * Ensures an element with the given className exists, and then returns the
+ * first element with the provided className.
+ * @see {goog.dom.query}
+ * @param {string} className the name of the class to look for.
+ * @param {!Element|!Document=} opt_root Optional element or document to look
+ *     in.
+ * @return {!Element} The first item with the class name provided.
+ * @throws {goog.asserts.AssertionError} Thrown if no element is found.
+ */
+goog.dom.getRequiredElementByClass = function(className, opt_root) {
+  var retValue = goog.dom.getElementByClass(className, opt_root);
+  return goog.asserts.assert(retValue,
+      'No element found with className: ' + className);
+};
+
+
+/**
+ * Prefer the standardized (http://www.w3.org/TR/selectors-api/), native and
+ * fast W3C Selectors API.
+ * @param {!(Element|Document)} parent The parent document object.
+ * @return {boolean} whether or not we can use parent.querySelector* APIs.
+ * @private
+ */
+goog.dom.canUseQuerySelector_ = function(parent) {
+  return !!(parent.querySelectorAll && parent.querySelector);
+};
+
+
+/**
+ * Helper for {@code getElementsByTagNameAndClass}.
+ * @param {!Document} doc The document to get the elements in.
+ * @param {?string=} opt_tag Element tag name.
+ * @param {?string=} opt_class Optional class name.
+ * @param {(Document|Element)=} opt_el Optional element to look in.
+ * @return { {length: number} } Array-like list of elements (only a length
+ *     property and numerical indices are guaranteed to exist).
+ * @private
+ */
+goog.dom.getElementsByTagNameAndClass_ = function(doc, opt_tag, opt_class,
+                                                  opt_el) {
+  var parent = opt_el || doc;
+  var tagName = (opt_tag && opt_tag != '*') ? opt_tag.toUpperCase() : '';
+
+  if (goog.dom.canUseQuerySelector_(parent) &&
+      (tagName || opt_class)) {
+    var query = tagName + (opt_class ? '.' + opt_class : '');
+    return parent.querySelectorAll(query);
+  }
+
+  // Use the native getElementsByClassName if available, under the assumption
+  // that even when the tag name is specified, there will be fewer elements to
+  // filter through when going by class than by tag name
+  if (opt_class && parent.getElementsByClassName) {
+    var els = parent.getElementsByClassName(opt_class);
+
+    if (tagName) {
+      var arrayLike = {};
+      var len = 0;
+
+      // Filter for specific tags if requested.
+      for (var i = 0, el; el = els[i]; i++) {
+        if (tagName == el.nodeName) {
+          arrayLike[len++] = el;
+        }
+      }
+      arrayLike.length = len;
+
+      return arrayLike;
+    } else {
+      return els;
+    }
+  }
+
+  var els = parent.getElementsByTagName(tagName || '*');
+
+  if (opt_class) {
+    var arrayLike = {};
+    var len = 0;
+    for (var i = 0, el; el = els[i]; i++) {
+      var className = el.className;
+      // Check if className has a split function since SVG className does not.
+      if (typeof className.split == 'function' &&
+          goog.array.contains(className.split(/\s+/), opt_class)) {
+        arrayLike[len++] = el;
+      }
+    }
+    arrayLike.length = len;
+    return arrayLike;
+  } else {
+    return els;
+  }
+};
+
+
+/**
+ * Alias for {@code getElementsByTagNameAndClass}.
+ * @param {?string=} opt_tag Element tag name.
+ * @param {?string=} opt_class Optional class name.
+ * @param {Element=} opt_el Optional element to look in.
+ * @return { {length: number} } Array-like list of elements (only a length
+ *     property and numerical indices are guaranteed to exist).
+ * @deprecated Use {@link goog.dom.getElementsByTagNameAndClass} instead.
+ */
+goog.dom.$$ = goog.dom.getElementsByTagNameAndClass;
+
+
+/**
+ * Sets multiple properties on a node.
+ * @param {Element} element DOM node to set properties on.
+ * @param {Object} properties Hash of property:value pairs.
+ */
+goog.dom.setProperties = function(element, properties) {
+  goog.object.forEach(properties, function(val, key) {
+    if (key == 'style') {
+      element.style.cssText = val;
+    } else if (key == 'class') {
+      element.className = val;
+    } else if (key == 'for') {
+      element.htmlFor = val;
+    } else if (key in goog.dom.DIRECT_ATTRIBUTE_MAP_) {
+      element.setAttribute(goog.dom.DIRECT_ATTRIBUTE_MAP_[key], val);
+    } else if (goog.string.startsWith(key, 'aria-') ||
+        goog.string.startsWith(key, 'data-')) {
+      element.setAttribute(key, val);
+    } else {
+      element[key] = val;
+    }
+  });
+};
+
+
+/**
+ * Map of attributes that should be set using
+ * element.setAttribute(key, val) instead of element[key] = val.  Used
+ * by goog.dom.setProperties.
+ *
+ * @private {!Object<string, string>}
+ * @const
+ */
+goog.dom.DIRECT_ATTRIBUTE_MAP_ = {
+  'cellpadding': 'cellPadding',
+  'cellspacing': 'cellSpacing',
+  'colspan': 'colSpan',
+  'frameborder': 'frameBorder',
+  'height': 'height',
+  'maxlength': 'maxLength',
+  'role': 'role',
+  'rowspan': 'rowSpan',
+  'type': 'type',
+  'usemap': 'useMap',
+  'valign': 'vAlign',
+  'width': 'width'
+};
+
+
+/**
+ * Gets the dimensions of the viewport.
+ *
+ * Gecko Standards mode:
+ * docEl.clientWidth  Width of viewport excluding scrollbar.
+ * win.innerWidth     Width of viewport including scrollbar.
+ * body.clientWidth   Width of body element.
+ *
+ * docEl.clientHeight Height of viewport excluding scrollbar.
+ * win.innerHeight    Height of viewport including scrollbar.
+ * body.clientHeight  Height of document.
+ *
+ * Gecko Backwards compatible mode:
+ * docEl.clientWidth  Width of viewport excluding scrollbar.
+ * win.innerWidth     Width of viewport including scrollbar.
+ * body.clientWidth   Width of viewport excluding scrollbar.
+ *
+ * docEl.clientHeight Height of document.
+ * win.innerHeight    Height of viewport including scrollbar.
+ * body.clientHeight  Height of viewport excluding scrollbar.
+ *
+ * IE6/7 Standards mode:
+ * docEl.clientWidth  Width of viewport excluding scrollbar.
+ * win.innerWidth     Undefined.
+ * body.clientWidth   Width of body element.
+ *
+ * docEl.clientHeight Height of viewport excluding scrollbar.
+ * win.innerHeight    Undefined.
+ * body.clientHeight  Height of document element.
+ *
+ * IE5 + IE6/7 Backwards compatible mode:
+ * docEl.clientWidth  0.
+ * win.innerWidth     Undefined.
+ * body.clientWidth   Width of viewport excluding scrollbar.
+ *
+ * docEl.clientHeight 0.
+ * win.innerHeight    Undefined.
+ * body.clientHeight  Height of viewport excluding scrollbar.
+ *
+ * Opera 9 Standards and backwards compatible mode:
+ * docEl.clientWidth  Width of viewport excluding scrollbar.
+ * win.innerWidth     Width of viewport including scrollbar.
+ * body.clientWidth   Width of viewport excluding scrollbar.
+ *
+ * docEl.clientHeight Height of document.
+ * win.innerHeight    Height of viewport including scrollbar.
+ * body.clientHeight  Height of viewport excluding scrollbar.
+ *
+ * WebKit:
+ * Safari 2
+ * docEl.clientHeight Same as scrollHeight.
+ * docEl.clientWidth  Same as innerWidth.
+ * win.innerWidth     Width of viewport excluding scrollbar.
+ * win.innerHeight    Height of the viewport including scrollbar.
+ * frame.innerHeight  Height of the viewport exluding scrollbar.
+ *
+ * Safari 3 (tested in 522)
+ *
+ * docEl.clientWidth  Width of viewport excluding scrollbar.
+ * docEl.clientHeight Height of viewport excluding scrollbar in strict mode.
+ * body.clientHeight  Height of viewport excluding scrollbar in quirks mode.
+ *
+ * @param {Window=} opt_window Optional window element to test.
+ * @return {!goog.math.Size} Object with values 'width' and 'height'.
+ */
+goog.dom.getViewportSize = function(opt_window) {
+  // TODO(arv): This should not take an argument
+  return goog.dom.getViewportSize_(opt_window || window);
+};
+
+
+/**
+ * Helper for {@code getViewportSize}.
+ * @param {Window} win The window to get the view port size for.
+ * @return {!goog.math.Size} Object with values 'width' and 'height'.
+ * @private
+ */
+goog.dom.getViewportSize_ = function(win) {
+  var doc = win.document;
+  var el = goog.dom.isCss1CompatMode_(doc) ? doc.documentElement : doc.body;
+  return new goog.math.Size(el.clientWidth, el.clientHeight);
+};
+
+
+/**
+ * Calculates the height of the document.
+ *
+ * @return {number} The height of the current document.
+ */
+goog.dom.getDocumentHeight = function() {
+  return goog.dom.getDocumentHeight_(window);
+};
+
+
+/**
+ * Calculates the height of the document of the given window.
+ *
+ * Function code copied from the opensocial gadget api:
+ *   gadgets.window.adjustHeight(opt_height)
+ *
+ * @private
+ * @param {!Window} win The window whose document height to retrieve.
+ * @return {number} The height of the document of the given window.
+ */
+goog.dom.getDocumentHeight_ = function(win) {
+  // NOTE(eae): This method will return the window size rather than the document
+  // size in webkit quirks mode.
+  var doc = win.document;
+  var height = 0;
+
+  if (doc) {
+    // Calculating inner content height is hard and different between
+    // browsers rendering in Strict vs. Quirks mode.  We use a combination of
+    // three properties within document.body and document.documentElement:
+    // - scrollHeight
+    // - offsetHeight
+    // - clientHeight
+    // These values differ significantly between browsers and rendering modes.
+    // But there are patterns.  It just takes a lot of time and persistence
+    // to figure out.
+
+    var body = doc.body;
+    var docEl = doc.documentElement;
+    if (!(docEl && body)) {
+      return 0;
+    }
+
+    // Get the height of the viewport
+    var vh = goog.dom.getViewportSize_(win).height;
+    if (goog.dom.isCss1CompatMode_(doc) && docEl.scrollHeight) {
+      // In Strict mode:
+      // The inner content height is contained in either:
+      //    document.documentElement.scrollHeight
+      //    document.documentElement.offsetHeight
+      // Based on studying the values output by different browsers,
+      // use the value that's NOT equal to the viewport height found above.
+      height = docEl.scrollHeight != vh ?
+          docEl.scrollHeight : docEl.offsetHeight;
+    } else {
+      // In Quirks mode:
+      // documentElement.clientHeight is equal to documentElement.offsetHeight
+      // except in IE.  In most browsers, document.documentElement can be used
+      // to calculate the inner content height.
+      // However, in other browsers (e.g. IE), document.body must be used
+      // instead.  How do we know which one to use?
+      // If document.documentElement.clientHeight does NOT equal
+      // document.documentElement.offsetHeight, then use document.body.
+      var sh = docEl.scrollHeight;
+      var oh = docEl.offsetHeight;
+      if (docEl.clientHeight != oh) {
+        sh = body.scrollHeight;
+        oh = body.offsetHeight;
+      }
+
+      // Detect whether the inner content height is bigger or smaller
+      // than the bounding box (viewport).  If bigger, take the larger
+      // value.  If smaller, take the smaller value.
+      if (sh > vh) {
+        // Content is larger
+        height = sh > oh ? sh : oh;
+      } else {
+        // Content is smaller
+        height = sh < oh ? sh : oh;
+      }
+    }
+  }
+
+  return height;
+};
+
+
+/**
+ * Gets the page scroll distance as a coordinate object.
+ *
+ * @param {Window=} opt_window Optional window element to test.
+ * @return {!goog.math.Coordinate} Object with values 'x' and 'y'.
+ * @deprecated Use {@link goog.dom.getDocumentScroll} instead.
+ */
+goog.dom.getPageScroll = function(opt_window) {
+  var win = opt_window || goog.global || window;
+  return goog.dom.getDomHelper(win.document).getDocumentScroll();
+};
+
+
+/**
+ * Gets the document scroll distance as a coordinate object.
+ *
+ * @return {!goog.math.Coordinate} Object with values 'x' and 'y'.
+ */
+goog.dom.getDocumentScroll = function() {
+  return goog.dom.getDocumentScroll_(document);
+};
+
+
+/**
+ * Helper for {@code getDocumentScroll}.
+ *
+ * @param {!Document} doc The document to get the scroll for.
+ * @return {!goog.math.Coordinate} Object with values 'x' and 'y'.
+ * @private
+ */
+goog.dom.getDocumentScroll_ = function(doc) {
+  var el = goog.dom.getDocumentScrollElement_(doc);
+  var win = goog.dom.getWindow_(doc);
+  if (goog.userAgent.IE && goog.userAgent.isVersionOrHigher('10') &&
+      win.pageYOffset != el.scrollTop) {
+    // The keyboard on IE10 touch devices shifts the page using the pageYOffset
+    // without modifying scrollTop. For this case, we want the body scroll
+    // offsets.
+    return new goog.math.Coordinate(el.scrollLeft, el.scrollTop);
+  }
+  return new goog.math.Coordinate(win.pageXOffset || el.scrollLeft,
+      win.pageYOffset || el.scrollTop);
+};
+
+
+/**
+ * Gets the document scroll element.
+ * @return {!Element} Scrolling element.
+ */
+goog.dom.getDocumentScrollElement = function() {
+  return goog.dom.getDocumentScrollElement_(document);
+};
+
+
+/**
+ * Helper for {@code getDocumentScrollElement}.
+ * @param {!Document} doc The document to get the scroll element for.
+ * @return {!Element} Scrolling element.
+ * @private
+ */
+goog.dom.getDocumentScrollElement_ = function(doc) {
+  // WebKit needs body.scrollLeft in both quirks mode and strict mode. We also
+  // default to the documentElement if the document does not have a body (e.g.
+  // a SVG document).
+  if (!goog.userAgent.WEBKIT && goog.dom.isCss1CompatMode_(doc)) {
+    return doc.documentElement;
+  }
+  return doc.body || doc.documentElement;
+};
+
+
+/**
+ * Gets the window object associated with the given document.
+ *
+ * @param {Document=} opt_doc  Document object to get window for.
+ * @return {!Window} The window associated with the given document.
+ */
+goog.dom.getWindow = function(opt_doc) {
+  // TODO(arv): This should not take an argument.
+  return opt_doc ? goog.dom.getWindow_(opt_doc) : window;
+};
+
+
+/**
+ * Helper for {@code getWindow}.
+ *
+ * @param {!Document} doc  Document object to get window for.
+ * @return {!Window} The window associated with the given document.
+ * @private
+ */
+goog.dom.getWindow_ = function(doc) {
+  return doc.parentWindow || doc.defaultView;
+};
+
+
+/**
+ * Returns a dom node with a set of attributes.  This function accepts varargs
+ * for subsequent nodes to be added.  Subsequent nodes will be added to the
+ * first node as childNodes.
+ *
+ * So:
+ * <code>createDom('div', null, createDom('p'), createDom('p'));</code>
+ * would return a div with two child paragraphs
+ *
+ * @param {string} tagName Tag to create.
+ * @param {(Object|Array<string>|string)=} opt_attributes If object, then a map
+ *     of name-value pairs for attributes. If a string, then this is the
+ *     className of the new element. If an array, the elements will be joined
+ *     together as the className of the new element.
+ * @param {...(Object|string|Array|NodeList)} var_args Further DOM nodes or
+ *     strings for text nodes. If one of the var_args is an array or NodeList,i
+ *     its elements will be added as childNodes instead.
+ * @return {!Element} Reference to a DOM node.
+ */
+goog.dom.createDom = function(tagName, opt_attributes, var_args) {
+  return goog.dom.createDom_(document, arguments);
+};
+
+
+/**
+ * Helper for {@code createDom}.
+ * @param {!Document} doc The document to create the DOM in.
+ * @param {!Arguments} args Argument object passed from the callers. See
+ *     {@code goog.dom.createDom} for details.
+ * @return {!Element} Reference to a DOM node.
+ * @private
+ */
+goog.dom.createDom_ = function(doc, args) {
+  var tagName = args[0];
+  var attributes = args[1];
+
+  // Internet Explorer is dumb: http://msdn.microsoft.com/workshop/author/
+  //                            dhtml/reference/properties/name_2.asp
+  // Also does not allow setting of 'type' attribute on 'input' or 'button'.
+  if (!goog.dom.BrowserFeature.CAN_ADD_NAME_OR_TYPE_ATTRIBUTES && attributes &&
+      (attributes.name || attributes.type)) {
+    var tagNameArr = ['<', tagName];
+    if (attributes.name) {
+      tagNameArr.push(' name="', goog.string.htmlEscape(attributes.name),
+                      '"');
+    }
+    if (attributes.type) {
+      tagNameArr.push(' type="', goog.string.htmlEscape(attributes.type),
+                      '"');
+
+      // Clone attributes map to remove 'type' without mutating the input.
+      var clone = {};
+      goog.object.extend(clone, attributes);
+
+      // JSCompiler can't see how goog.object.extend added this property,
+      // because it was essentially added by reflection.
+      // So it needs to be quoted.
+      delete clone['type'];
+
+      attributes = clone;
+    }
+    tagNameArr.push('>');
+    tagName = tagNameArr.join('');
+  }
+
+  var element = doc.createElement(tagName);
+
+  if (attributes) {
+    if (goog.isString(attributes)) {
+      element.className = attributes;
+    } else if (goog.isArray(attributes)) {
+      element.className = attributes.join(' ');
+    } else {
+      goog.dom.setProperties(element, attributes);
+    }
+  }
+
+  if (args.length > 2) {
+    goog.dom.append_(doc, element, args, 2);
+  }
+
+  return element;
+};
+
+
+/**
+ * Appends a node with text or other nodes.
+ * @param {!Document} doc The document to create new nodes in.
+ * @param {!Node} parent The node to append nodes to.
+ * @param {!Arguments} args The values to add. See {@code goog.dom.append}.
+ * @param {number} startIndex The index of the array to start from.
+ * @private
+ */
+goog.dom.append_ = function(doc, parent, args, startIndex) {
+  function childHandler(child) {
+    // TODO(user): More coercion, ala MochiKit?
+    if (child) {
+      parent.appendChild(goog.isString(child) ?
+          doc.createTextNode(child) : child);
+    }
+  }
+
+  for (var i = startIndex; i < args.length; i++) {
+    var arg = args[i];
+    // TODO(attila): Fix isArrayLike to return false for a text node.
+    if (goog.isArrayLike(arg) && !goog.dom.isNodeLike(arg)) {
+      // If the argument is a node list, not a real array, use a clone,
+      // because forEach can't be used to mutate a NodeList.
+      goog.array.forEach(goog.dom.isNodeList(arg) ?
+          goog.array.toArray(arg) : arg,
+          childHandler);
+    } else {
+      childHandler(arg);
+    }
+  }
+};
+
+
+/**
+ * Alias for {@code createDom}.
+ * @param {string} tagName Tag to create.
+ * @param {(string|Object)=} opt_attributes If object, then a map of name-value
+ *     pairs for attributes. If a string, then this is the className of the new
+ *     element.
+ * @param {...(Object|string|Array|NodeList)} var_args Further DOM nodes or
+ *     strings for text nodes. If one of the var_args is an array, its
+ *     children will be added as childNodes instead.
+ * @return {!Element} Reference to a DOM node.
+ * @deprecated Use {@link goog.dom.createDom} instead.
+ */
+goog.dom.$dom = goog.dom.createDom;
+
+
+/**
+ * Creates a new element.
+ * @param {string} name Tag name.
+ * @return {!Element} The new element.
+ */
+goog.dom.createElement = function(name) {
+  return document.createElement(name);
+};
+
+
+/**
+ * Creates a new text node.
+ * @param {number|string} content Content.
+ * @return {!Text} The new text node.
+ */
+goog.dom.createTextNode = function(content) {
+  return document.createTextNode(String(content));
+};
+
+
+/**
+ * Create a table.
+ * @param {number} rows The number of rows in the table.  Must be >= 1.
+ * @param {number} columns The number of columns in the table.  Must be >= 1.
+ * @param {boolean=} opt_fillWithNbsp If true, fills table entries with
+ *     {@code goog.string.Unicode.NBSP} characters.
+ * @return {!Element} The created table.
+ */
+goog.dom.createTable = function(rows, columns, opt_fillWithNbsp) {
+  // TODO(user): Return HTMLTableElement, also in prototype function.
+  // Callers need to be updated to e.g. not assign numbers to table.cellSpacing.
+  return goog.dom.createTable_(document, rows, columns, !!opt_fillWithNbsp);
+};
+
+
+/**
+ * Create a table.
+ * @param {!Document} doc Document object to use to create the table.
+ * @param {number} rows The number of rows in the table.  Must be >= 1.
+ * @param {number} columns The number of columns in the table.  Must be >= 1.
+ * @param {boolean} fillWithNbsp If true, fills table entries with
+ *     {@code goog.string.Unicode.NBSP} characters.
+ * @return {!HTMLTableElement} The created table.
+ * @private
+ */
+goog.dom.createTable_ = function(doc, rows, columns, fillWithNbsp) {
+  var table = /** @type {!HTMLTableElement} */
+      (doc.createElement(goog.dom.TagName.TABLE));
+  var tbody = table.appendChild(doc.createElement(goog.dom.TagName.TBODY));
+  for (var i = 0; i < rows; i++) {
+    var tr = doc.createElement(goog.dom.TagName.TR);
+    for (var j = 0; j < columns; j++) {
+      var td = doc.createElement(goog.dom.TagName.TD);
+      // IE <= 9 will create a text node if we set text content to the empty
+      // string, so we avoid doing it unless necessary. This ensures that the
+      // same DOM tree is returned on all browsers.
+      if (fillWithNbsp) {
+        goog.dom.setTextContent(td, goog.string.Unicode.NBSP);
+      }
+      tr.appendChild(td);
+    }
+    tbody.appendChild(tr);
+  }
+  return table;
+};
+
+
+/**
+ * Converts HTML markup into a node.
+ * @param {!goog.html.SafeHtml} html The HTML markup to convert.
+ * @return {!Node} The resulting node.
+ */
+goog.dom.safeHtmlToNode = function(html) {
+  return goog.dom.safeHtmlToNode_(document, html);
+};
+
+
+/**
+ * Helper for {@code safeHtmlToNode}.
+ * @param {!Document} doc The document.
+ * @param {!goog.html.SafeHtml} html The HTML markup to convert.
+ * @return {!Node} The resulting node.
+ * @private
+ */
+goog.dom.safeHtmlToNode_ = function(doc, html) {
+  var tempDiv = doc.createElement(goog.dom.TagName.DIV);
+  if (goog.dom.BrowserFeature.INNER_HTML_NEEDS_SCOPED_ELEMENT) {
+    goog.dom.safe.setInnerHtml(tempDiv,
+        goog.html.SafeHtml.concat(goog.html.SafeHtml.create('br'), html));
+    tempDiv.removeChild(tempDiv.firstChild);
+  } else {
+    goog.dom.safe.setInnerHtml(tempDiv, html);
+  }
+  return goog.dom.childrenToNode_(doc, tempDiv);
+};
+
+
+/**
+ * Converts an HTML string into a document fragment. The string must be
+ * sanitized in order to avoid cross-site scripting. For example
+ * {@code goog.dom.htmlToDocumentFragment('&lt;img src=x onerror=alert(0)&gt;')}
+ * triggers an alert in all browsers, even if the returned document fragment
+ * is thrown away immediately.
+ *
+ * @param {string} htmlString The HTML string to convert.
+ * @return {!Node} The resulting document fragment.
+ */
+goog.dom.htmlToDocumentFragment = function(htmlString) {
+  return goog.dom.htmlToDocumentFragment_(document, htmlString);
+};
+
+
+// TODO(jakubvrana): Merge with {@code safeHtmlToNode_}.
+/**
+ * Helper for {@code htmlToDocumentFragment}.
+ *
+ * @param {!Document} doc The document.
+ * @param {string} htmlString The HTML string to convert.
+ * @return {!Node} The resulting document fragment.
+ * @private
+ */
+goog.dom.htmlToDocumentFragment_ = function(doc, htmlString) {
+  var tempDiv = doc.createElement(goog.dom.TagName.DIV);
+  if (goog.dom.BrowserFeature.INNER_HTML_NEEDS_SCOPED_ELEMENT) {
+    tempDiv.innerHTML = '<br>' + htmlString;
+    tempDiv.removeChild(tempDiv.firstChild);
+  } else {
+    tempDiv.innerHTML = htmlString;
+  }
+  return goog.dom.childrenToNode_(doc, tempDiv);
+};
+
+
+/**
+ * Helper for {@code htmlToDocumentFragment_}.
+ * @param {!Document} doc The document.
+ * @param {!Node} tempDiv The input node.
+ * @return {!Node} The resulting node.
+ * @private
+ */
+goog.dom.childrenToNode_ = function(doc, tempDiv) {
+  if (tempDiv.childNodes.length == 1) {
+    return tempDiv.removeChild(tempDiv.firstChild);
+  } else {
+    var fragment = doc.createDocumentFragment();
+    while (tempDiv.firstChild) {
+      fragment.appendChild(tempDiv.firstChild);
+    }
+    return fragment;
+  }
+};
+
+
+/**
+ * Returns true if the browser is in "CSS1-compatible" (standards-compliant)
+ * mode, false otherwise.
+ * @return {boolean} True if in CSS1-compatible mode.
+ */
+goog.dom.isCss1CompatMode = function() {
+  return goog.dom.isCss1CompatMode_(document);
+};
+
+
+/**
+ * Returns true if the browser is in "CSS1-compatible" (standards-compliant)
+ * mode, false otherwise.
+ * @param {!Document} doc The document to check.
+ * @return {boolean} True if in CSS1-compatible mode.
+ * @private
+ */
+goog.dom.isCss1CompatMode_ = function(doc) {
+  if (goog.dom.COMPAT_MODE_KNOWN_) {
+    return goog.dom.ASSUME_STANDARDS_MODE;
+  }
+
+  return doc.compatMode == 'CSS1Compat';
+};
+
+
+/**
+ * Determines if the given node can contain children, intended to be used for
+ * HTML generation.
+ *
+ * IE natively supports node.canHaveChildren but has inconsistent behavior.
+ * Prior to IE8 the base tag allows children and in IE9 all nodes return true
+ * for canHaveChildren.
+ *
+ * In practice all non-IE browsers allow you to add children to any node, but
+ * the behavior is inconsistent:
+ *
+ * <pre>
+ *   var a = document.createElement(goog.dom.TagName.BR);
+ *   a.appendChild(document.createTextNode('foo'));
+ *   a.appendChild(document.createTextNode('bar'));
+ *   console.log(a.childNodes.length);  // 2
+ *   console.log(a.innerHTML);  // Chrome: "", IE9: "foobar", FF3.5: "foobar"
+ * </pre>
+ *
+ * For more information, see:
+ * http://dev.w3.org/html5/markup/syntax.html#syntax-elements
+ *
+ * TODO(user): Rename shouldAllowChildren() ?
+ *
+ * @param {Node} node The node to check.
+ * @return {boolean} Whether the node can contain children.
+ */
+goog.dom.canHaveChildren = function(node) {
+  if (node.nodeType != goog.dom.NodeType.ELEMENT) {
+    return false;
+  }
+  switch (node.tagName) {
+    case goog.dom.TagName.APPLET:
+    case goog.dom.TagName.AREA:
+    case goog.dom.TagName.BASE:
+    case goog.dom.TagName.BR:
+    case goog.dom.TagName.COL:
+    case goog.dom.TagName.COMMAND:
+    case goog.dom.TagName.EMBED:
+    case goog.dom.TagName.FRAME:
+    case goog.dom.TagName.HR:
+    case goog.dom.TagName.IMG:
+    case goog.dom.TagName.INPUT:
+    case goog.dom.TagName.IFRAME:
+    case goog.dom.TagName.ISINDEX:
+    case goog.dom.TagName.KEYGEN:
+    case goog.dom.TagName.LINK:
+    case goog.dom.TagName.NOFRAMES:
+    case goog.dom.TagName.NOSCRIPT:
+    case goog.dom.TagName.META:
+    case goog.dom.TagName.OBJECT:
+    case goog.dom.TagName.PARAM:
+    case goog.dom.TagName.SCRIPT:
+    case goog.dom.TagName.SOURCE:
+    case goog.dom.TagName.STYLE:
+    case goog.dom.TagName.TRACK:
+    case goog.dom.TagName.WBR:
+      return false;
+  }
+  return true;
+};
+
+
+/**
+ * Appends a child to a node.
+ * @param {Node} parent Parent.
+ * @param {Node} child Child.
+ */
+goog.dom.appendChild = function(parent, child) {
+  parent.appendChild(child);
+};
+
+
+/**
+ * Appends a node with text or other nodes.
+ * @param {!Node} parent The node to append nodes to.
+ * @param {...goog.dom.Appendable} var_args The things to append to the node.
+ *     If this is a Node it is appended as is.
+ *     If this is a string then a text node is appended.
+ *     If this is an array like object then fields 0 to length - 1 are appended.
+ */
+goog.dom.append = function(parent, var_args) {
+  goog.dom.append_(goog.dom.getOwnerDocument(parent), parent, arguments, 1);
+};
+
+
+/**
+ * Removes all the child nodes on a DOM node.
+ * @param {Node} node Node to remove children from.
+ */
+goog.dom.removeChildren = function(node) {
+  // Note: Iterations over live collections can be slow, this is the fastest
+  // we could find. The double parenthesis are used to prevent JsCompiler and
+  // strict warnings.
+  var child;
+  while ((child = node.firstChild)) {
+    node.removeChild(child);
+  }
+};
+
+
+/**
+ * Inserts a new node before an existing reference node (i.e. as the previous
+ * sibling). If the reference node has no parent, then does nothing.
+ * @param {Node} newNode Node to insert.
+ * @param {Node} refNode Reference node to insert before.
+ */
+goog.dom.insertSiblingBefore = function(newNode, refNode) {
+  if (refNode.parentNode) {
+    refNode.parentNode.insertBefore(newNode, refNode);
+  }
+};
+
+
+/**
+ * Inserts a new node after an existing reference node (i.e. as the next
+ * sibling). If the reference node has no parent, then does nothing.
+ * @param {Node} newNode Node to insert.
+ * @param {Node} refNode Reference node to insert after.
+ */
+goog.dom.insertSiblingAfter = function(newNode, refNode) {
+  if (refNode.parentNode) {
+    refNode.parentNode.insertBefore(newNode, refNode.nextSibling);
+  }
+};
+
+
+/**
+ * Insert a child at a given index. If index is larger than the number of child
+ * nodes that the parent currently has, the node is inserted as the last child
+ * node.
+ * @param {Element} parent The element into which to insert the child.
+ * @param {Node} child The element to insert.
+ * @param {number} index The index at which to insert the new child node. Must
+ *     not be negative.
+ */
+goog.dom.insertChildAt = function(parent, child, index) {
+  // Note that if the second argument is null, insertBefore
+  // will append the child at the end of the list of children.
+  parent.insertBefore(child, parent.childNodes[index] || null);
+};
+
+
+/**
+ * Removes a node from its parent.
+ * @param {Node} node The node to remove.
+ * @return {Node} The node removed if removed; else, null.
+ */
+goog.dom.removeNode = function(node) {
+  return node && node.parentNode ? node.parentNode.removeChild(node) : null;
+};
+
+
+/**
+ * Replaces a node in the DOM tree. Will do nothing if {@code oldNode} has no
+ * parent.
+ * @param {Node} newNode Node to insert.
+ * @param {Node} oldNode Node to replace.
+ */
+goog.dom.replaceNode = function(newNode, oldNode) {
+  var parent = oldNode.parentNode;
+  if (parent) {
+    parent.replaceChild(newNode, oldNode);
+  }
+};
+
+
+/**
+ * Flattens an element. That is, removes it and replace it with its children.
+ * Does nothing if the element is not in the document.
+ * @param {Element} element The element to flatten.
+ * @return {Element|undefined} The original element, detached from the document
+ *     tree, sans children; or undefined, if the element was not in the document
+ *     to begin with.
+ */
+goog.dom.flattenElement = function(element) {
+  var child, parent = element.parentNode;
+  if (parent && parent.nodeType != goog.dom.NodeType.DOCUMENT_FRAGMENT) {
+    // Use IE DOM method (supported by Opera too) if available
+    if (element.removeNode) {
+      return /** @type {Element} */ (element.removeNode(false));
+    } else {
+      // Move all children of the original node up one level.
+      while ((child = element.firstChild)) {
+        parent.insertBefore(child, element);
+      }
+
+      // Detach the original element.
+      return /** @type {Element} */ (goog.dom.removeNode(element));
+    }
+  }
+};
+
+
+/**
+ * Returns an array containing just the element children of the given element.
+ * @param {Element} element The element whose element children we want.
+ * @return {!(Array|NodeList)} An array or array-like list of just the element
+ *     children of the given element.
+ */
+goog.dom.getChildren = function(element) {
+  // We check if the children attribute is supported for child elements
+  // since IE8 misuses the attribute by also including comments.
+  if (goog.dom.BrowserFeature.CAN_USE_CHILDREN_ATTRIBUTE &&
+      element.children != undefined) {
+    return element.children;
+  }
+  // Fall back to manually filtering the element's child nodes.
+  return goog.array.filter(element.childNodes, function(node) {
+    return node.nodeType == goog.dom.NodeType.ELEMENT;
+  });
+};
+
+
+/**
+ * Returns the first child node that is an element.
+ * @param {Node} node The node to get the first child element of.
+ * @return {Element} The first child node of {@code node} that is an element.
+ */
+goog.dom.getFirstElementChild = function(node) {
+  if (node.firstElementChild != undefined) {
+    return /** @type {!Element} */(node).firstElementChild;
+  }
+  return goog.dom.getNextElementNode_(node.firstChild, true);
+};
+
+
+/**
+ * Returns the last child node that is an element.
+ * @param {Node} node The node to get the last child element of.
+ * @return {Element} The last child node of {@code node} that is an element.
+ */
+goog.dom.getLastElementChild = function(node) {
+  if (node.lastElementChild != undefined) {
+    return /** @type {!Element} */(node).lastElementChild;
+  }
+  return goog.dom.getNextElementNode_(node.lastChild, false);
+};
+
+
+/**
+ * Returns the first next sibling that is an element.
+ * @param {Node} node The node to get the next sibling element of.
+ * @return {Element} The next sibling of {@code node} that is an element.
+ */
+goog.dom.getNextElementSibling = function(node) {
+  if (node.nextElementSibling != undefined) {
+    return /** @type {!Element} */(node).nextElementSibling;
+  }
+  return goog.dom.getNextElementNode_(node.nextSibling, true);
+};
+
+
+/**
+ * Returns the first previous sibling that is an element.
+ * @param {Node} node The node to get the previous sibling element of.
+ * @return {Element} The first previous sibling of {@code node} that is
+ *     an element.
+ */
+goog.dom.getPreviousElementSibling = function(node) {
+  if (node.previousElementSibling != undefined) {
+    return /** @type {!Element} */(node).previousElementSibling;
+  }
+  return goog.dom.getNextElementNode_(node.previousSibling, false);
+};
+
+
+/**
+ * Returns the first node that is an element in the specified direction,
+ * starting with {@code node}.
+ * @param {Node} node The node to get the next element from.
+ * @param {boolean} forward Whether to look forwards or backwards.
+ * @return {Element} The first element.
+ * @private
+ */
+goog.dom.getNextElementNode_ = function(node, forward) {
+  while (node && node.nodeType != goog.dom.NodeType.ELEMENT) {
+    node = forward ? node.nextSibling : node.previousSibling;
+  }
+
+  return /** @type {Element} */ (node);
+};
+
+
+/**
+ * Returns the next node in source order from the given node.
+ * @param {Node} node The node.
+ * @return {Node} The next node in the DOM tree, or null if this was the last
+ *     node.
+ */
+goog.dom.getNextNode = function(node) {
+  if (!node) {
+    return null;
+  }
+
+  if (node.firstChild) {
+    return node.firstChild;
+  }
+
+  while (node && !node.nextSibling) {
+    node = node.parentNode;
+  }
+
+  return node ? node.nextSibling : null;
+};
+
+
+/**
+ * Returns the previous node in source order from the given node.
+ * @param {Node} node The node.
+ * @return {Node} The previous node in the DOM tree, or null if this was the
+ *     first node.
+ */
+goog.dom.getPreviousNode = function(node) {
+  if (!node) {
+    return null;
+  }
+
+  if (!node.previousSibling) {
+    return node.parentNode;
+  }
+
+  node = node.previousSibling;
+  while (node && node.lastChild) {
+    node = node.lastChild;
+  }
+
+  return node;
+};
+
+
+/**
+ * Whether the object looks like a DOM node.
+ * @param {?} obj The object being tested for node likeness.
+ * @return {boolean} Whether the object looks like a DOM node.
+ */
+goog.dom.isNodeLike = function(obj) {
+  return goog.isObject(obj) && obj.nodeType > 0;
+};
+
+
+/**
+ * Whether the object looks like an Element.
+ * @param {?} obj The object being tested for Element likeness.
+ * @return {boolean} Whether the object looks like an Element.
+ */
+goog.dom.isElement = function(obj) {
+  return goog.isObject(obj) && obj.nodeType == goog.dom.NodeType.ELEMENT;
+};
+
+
+/**
+ * Returns true if the specified value is a Window object. This includes the
+ * global window for HTML pages, and iframe windows.
+ * @param {?} obj Variable to test.
+ * @return {boolean} Whether the variable is a window.
+ */
+goog.dom.isWindow = function(obj) {
+  return goog.isObject(obj) && obj['window'] == obj;
+};
+
+
+/**
+ * Returns an element's parent, if it's an Element.
+ * @param {Element} element The DOM element.
+ * @return {Element} The parent, or null if not an Element.
+ */
+goog.dom.getParentElement = function(element) {
+  var parent;
+  if (goog.dom.BrowserFeature.CAN_USE_PARENT_ELEMENT_PROPERTY) {
+    var isIe9 = goog.userAgent.IE &&
+        goog.userAgent.isVersionOrHigher('9') &&
+        !goog.userAgent.isVersionOrHigher('10');
+    // SVG elements in IE9 can't use the parentElement property.
+    // goog.global['SVGElement'] is not defined in IE9 quirks mode.
+    if (!(isIe9 && goog.global['SVGElement'] &&
+        element instanceof goog.global['SVGElement'])) {
+      parent = element.parentElement;
+      if (parent) {
+        return parent;
+      }
+    }
+  }
+  parent = element.parentNode;
+  return goog.dom.isElement(parent) ? /** @type {!Element} */ (parent) : null;
+};
+
+
+/**
+ * Whether a node contains another node.
+ * @param {Node} parent The node that should contain the other node.
+ * @param {Node} descendant The node to test presence of.
+ * @return {boolean} Whether the parent node contains the descendent node.
+ */
+goog.dom.contains = function(parent, descendant) {
+  // We use browser specific methods for this if available since it is faster
+  // that way.
+
+  // IE DOM
+  if (parent.contains && descendant.nodeType == goog.dom.NodeType.ELEMENT) {
+    return parent == descendant || parent.contains(descendant);
+  }
+
+  // W3C DOM Level 3
+  if (typeof parent.compareDocumentPosition != 'undefined') {
+    return parent == descendant ||
+        Boolean(parent.compareDocumentPosition(descendant) & 16);
+  }
+
+  // W3C DOM Level 1
+  while (descendant && parent != descendant) {
+    descendant = descendant.parentNode;
+  }
+  return descendant == parent;
+};
+
+
+/**
+ * Compares the document order of two nodes, returning 0 if they are the same
+ * node, a negative number if node1 is before node2, and a positive number if
+ * node2 is before node1.  Note that we compare the order the tags appear in the
+ * document so in the tree <b><i>text</i></b> the B node is considered to be
+ * before the I node.
+ *
+ * @param {Node} node1 The first node to compare.
+ * @param {Node} node2 The second node to compare.
+ * @return {number} 0 if the nodes are the same node, a negative number if node1
+ *     is before node2, and a positive number if node2 is before node1.
+ */
+goog.dom.compareNodeOrder = function(node1, node2) {
+  // Fall out quickly for equality.
+  if (node1 == node2) {
+    return 0;
+  }
+
+  // Use compareDocumentPosition where available
+  if (node1.compareDocumentPosition) {
+    // 4 is the bitmask for FOLLOWS.
+    return node1.compareDocumentPosition(node2) & 2 ? 1 : -1;
+  }
+
+  // Special case for document nodes on IE 7 and 8.
+  if (goog.userAgent.IE && !goog.userAgent.isDocumentModeOrHigher(9)) {
+    if (node1.nodeType == goog.dom.NodeType.DOCUMENT) {
+      return -1;
+    }
+    if (node2.nodeType == goog.dom.NodeType.DOCUMENT) {
+      return 1;
+    }
+  }
+
+  // Process in IE using sourceIndex - we check to see if the first node has
+  // a source index or if its parent has one.
+  if ('sourceIndex' in node1 ||
+      (node1.parentNode && 'sourceIndex' in node1.parentNode)) {
+    var isElement1 = node1.nodeType == goog.dom.NodeType.ELEMENT;
+    var isElement2 = node2.nodeType == goog.dom.NodeType.ELEMENT;
+
+    if (isElement1 && isElement2) {
+      return node1.sourceIndex - node2.sourceIndex;
+    } else {
+      var parent1 = node1.parentNode;
+      var parent2 = node2.parentNode;
+
+      if (parent1 == parent2) {
+        return goog.dom.compareSiblingOrder_(node1, node2);
+      }
+
+      if (!isElement1 && goog.dom.contains(parent1, node2)) {
+        return -1 * goog.dom.compareParentsDescendantNodeIe_(node1, node2);
+      }
+
+
+      if (!isElement2 && goog.dom.contains(parent2, node1)) {
+        return goog.dom.compareParentsDescendantNodeIe_(node2, node1);
+      }
+
+      return (isElement1 ? node1.sourceIndex : parent1.sourceIndex) -
+             (isElement2 ? node2.sourceIndex : parent2.sourceIndex);
+    }
+  }
+
+  // For Safari, we compare ranges.
+  var doc = goog.dom.getOwnerDocument(node1);
+
+  var range1, range2;
+  range1 = doc.createRange();
+  range1.selectNode(node1);
+  range1.collapse(true);
+
+  range2 = doc.createRange();
+  range2.selectNode(node2);
+  range2.collapse(true);
+
+  return range1.compareBoundaryPoints(goog.global['Range'].START_TO_END,
+      range2);
+};
+
+
+/**
+ * Utility function to compare the position of two nodes, when
+ * {@code textNode}'s parent is an ancestor of {@code node}.  If this entry
+ * condition is not met, this function will attempt to reference a null object.
+ * @param {!Node} textNode The textNode to compare.
+ * @param {Node} node The node to compare.
+ * @return {number} -1 if node is before textNode, +1 otherwise.
+ * @private
+ */
+goog.dom.compareParentsDescendantNodeIe_ = function(textNode, node) {
+  var parent = textNode.parentNode;
+  if (parent == node) {
+    // If textNode is a child of node, then node comes first.
+    return -1;
+  }
+  var sibling = node;
+  while (sibling.parentNode != parent) {
+    sibling = sibling.parentNode;
+  }
+  return goog.dom.compareSiblingOrder_(sibling, textNode);
+};
+
+
+/**
+ * Utility function to compare the position of two nodes known to be non-equal
+ * siblings.
+ * @param {Node} node1 The first node to compare.
+ * @param {!Node} node2 The second node to compare.
+ * @return {number} -1 if node1 is before node2, +1 otherwise.
+ * @private
+ */
+goog.dom.compareSiblingOrder_ = function(node1, node2) {
+  var s = node2;
+  while ((s = s.previousSibling)) {
+    if (s == node1) {
+      // We just found node1 before node2.
+      return -1;
+    }
+  }
+
+  // Since we didn't find it, node1 must be after node2.
+  return 1;
+};
+
+
+/**
+ * Find the deepest common ancestor of the given nodes.
+ * @param {...Node} var_args The nodes to find a common ancestor of.
+ * @return {Node} The common ancestor of the nodes, or null if there is none.
+ *     null will only be returned if two or more of the nodes are from different
+ *     documents.
+ */
+goog.dom.findCommonAncestor = function(var_args) {
+  var i, count = arguments.length;
+  if (!count) {
+    return null;
+  } else if (count == 1) {
+    return arguments[0];
+  }
+
+  var paths = [];
+  var minLength = Infinity;
+  for (i = 0; i < count; i++) {
+    // Compute the list of ancestors.
+    var ancestors = [];
+    var node = arguments[i];
+    while (node) {
+      ancestors.unshift(node);
+      node = node.parentNode;
+    }
+
+    // Save the list for comparison.
+    paths.push(ancestors);
+    minLength = Math.min(minLength, ancestors.length);
+  }
+  var output = null;
+  for (i = 0; i < minLength; i++) {
+    var first = paths[0][i];
+    for (var j = 1; j < count; j++) {
+      if (first != paths[j][i]) {
+        return output;
+      }
+    }
+    output = first;
+  }
+  return output;
+};
+
+
+/**
+ * Returns the owner document for a node.
+ * @param {Node|Window} node The node to get the document for.
+ * @return {!Document} The document owning the node.
+ */
+goog.dom.getOwnerDocument = function(node) {
+  // TODO(nnaze): Update param signature to be non-nullable.
+  goog.asserts.assert(node, 'Node cannot be null or undefined.');
+  return /** @type {!Document} */ (
+      node.nodeType == goog.dom.NodeType.DOCUMENT ? node :
+      node.ownerDocument || node.document);
+};
+
+
+/**
+ * Cross-browser function for getting the document element of a frame or iframe.
+ * @param {Element} frame Frame element.
+ * @return {!Document} The frame content document.
+ */
+goog.dom.getFrameContentDocument = function(frame) {
+  var doc = frame.contentDocument || frame.contentWindow.document;
+  return doc;
+};
+
+
+/**
+ * Cross-browser function for getting the window of a frame or iframe.
+ * @param {Element} frame Frame element.
+ * @return {Window} The window associated with the given frame.
+ */
+goog.dom.getFrameContentWindow = function(frame) {
+  return frame.contentWindow ||
+      goog.dom.getWindow(goog.dom.getFrameContentDocument(frame));
+};
+
+
+/**
+ * Sets the text content of a node, with cross-browser support.
+ * @param {Node} node The node to change the text content of.
+ * @param {string|number} text The value that should replace the node's content.
+ */
+goog.dom.setTextContent = function(node, text) {
+  goog.asserts.assert(node != null,
+      'goog.dom.setTextContent expects a non-null value for node');
+
+  if ('textContent' in node) {
+    node.textContent = text;
+  } else if (node.nodeType == goog.dom.NodeType.TEXT) {
+    node.data = text;
+  } else if (node.firstChild &&
+             node.firstChild.nodeType == goog.dom.NodeType.TEXT) {
+    // If the first child is a text node we just change its data and remove the
+    // rest of the children.
+    while (node.lastChild != node.firstChild) {
+      node.removeChild(node.lastChild);
+    }
+    node.firstChild.data = text;
+  } else {
+    goog.dom.removeChildren(node);
+    var doc = goog.dom.getOwnerDocument(node);
+    node.appendChild(doc.createTextNode(String(text)));
+  }
+};
+
+
+/**
+ * Gets the outerHTML of a node, which islike innerHTML, except that it
+ * actually contains the HTML of the node itself.
+ * @param {Element} element The element to get the HTML of.
+ * @return {string} The outerHTML of the given element.
+ */
+goog.dom.getOuterHtml = function(element) {
+  // IE, Opera and WebKit all have outerHTML.
+  if ('outerHTML' in element) {
+    return element.outerHTML;
+  } else {
+    var doc = goog.dom.getOwnerDocument(element);
+    var div = doc.createElement(goog.dom.TagName.DIV);
+    div.appendChild(element.cloneNode(true));
+    return div.innerHTML;
+  }
+};
+
+
+/**
+ * Finds the first descendant node that matches the filter function, using
+ * a depth first search. This function offers the most general purpose way
+ * of finding a matching element. You may also wish to consider
+ * {@code goog.dom.query} which can express many matching criteria using
+ * CSS selector expressions. These expressions often result in a more
+ * compact representation of the desired result.
+ * @see goog.dom.query
+ *
+ * @param {Node} root The root of the tree to search.
+ * @param {function(Node) : boolean} p The filter function.
+ * @return {Node|undefined} The found node or undefined if none is found.
+ */
+goog.dom.findNode = function(root, p) {
+  var rv = [];
+  var found = goog.dom.findNodes_(root, p, rv, true);
+  return found ? rv[0] : undefined;
+};
+
+
+/**
+ * Finds all the descendant nodes that match the filter function, using a
+ * a depth first search. This function offers the most general-purpose way
+ * of finding a set of matching elements. You may also wish to consider
+ * {@code goog.dom.query} which can express many matching criteria using
+ * CSS selector expressions. These expressions often result in a more
+ * compact representation of the desired result.
+
+ * @param {Node} root The root of the tree to search.
+ * @param {function(Node) : boolean} p The filter function.
+ * @return {!Array<!Node>} The found nodes or an empty array if none are found.
+ */
+goog.dom.findNodes = function(root, p) {
+  var rv = [];
+  goog.dom.findNodes_(root, p, rv, false);
+  return rv;
+};
+
+
+/**
+ * Finds the first or all the descendant nodes that match the filter function,
+ * using a depth first search.
+ * @param {Node} root The root of the tree to search.
+ * @param {function(Node) : boolean} p The filter function.
+ * @param {!Array<!Node>} rv The found nodes are added to this array.
+ * @param {boolean} findOne If true we exit after the first found node.
+ * @return {boolean} Whether the search is complete or not. True in case findOne
+ *     is true and the node is found. False otherwise.
+ * @private
+ */
+goog.dom.findNodes_ = function(root, p, rv, findOne) {
+  if (root != null) {
+    var child = root.firstChild;
+    while (child) {
+      if (p(child)) {
+        rv.push(child);
+        if (findOne) {
+          return true;
+        }
+      }
+      if (goog.dom.findNodes_(child, p, rv, findOne)) {
+        return true;
+      }
+      child = child.nextSibling;
+    }
+  }
+  return false;
+};
+
+
+/**
+ * Map of tags whose content to ignore when calculating text length.
+ * @private {!Object<string, number>}
+ * @const
+ */
+goog.dom.TAGS_TO_IGNORE_ = {
+  'SCRIPT': 1,
+  'STYLE': 1,
+  'HEAD': 1,
+  'IFRAME': 1,
+  'OBJECT': 1
+};
+
+
+/**
+ * Map of tags which have predefined values with regard to whitespace.
+ * @private {!Object<string, string>}
+ * @const
+ */
+goog.dom.PREDEFINED_TAG_VALUES_ = {'IMG': ' ', 'BR': '\n'};
+
+
+/**
+ * Returns true if the element has a tab index that allows it to receive
+ * keyboard focus (tabIndex >= 0), false otherwise.  Note that some elements
+ * natively support keyboard focus, even if they have no tab index.
+ * @param {!Element} element Element to check.
+ * @return {boolean} Whether the element has a tab index that allows keyboard
+ *     focus.
+ * @see http://fluidproject.org/blog/2008/01/09/getting-setting-and-removing-tabindex-values-with-javascript/
+ */
+goog.dom.isFocusableTabIndex = function(element) {
+  return goog.dom.hasSpecifiedTabIndex_(element) &&
+         goog.dom.isTabIndexFocusable_(element);
+};
+
+
+/**
+ * Enables or disables keyboard focus support on the element via its tab index.
+ * Only elements for which {@link goog.dom.isFocusableTabIndex} returns true
+ * (or elements that natively support keyboard focus, like form elements) can
+ * receive keyboard focus.  See http://go/tabindex for more info.
+ * @param {Element} element Element whose tab index is to be changed.
+ * @param {boolean} enable Whether to set or remove a tab index on the element
+ *     that supports keyboard focus.
+ */
+goog.dom.setFocusableTabIndex = function(element, enable) {
+  if (enable) {
+    element.tabIndex = 0;
+  } else {
+    // Set tabIndex to -1 first, then remove it. This is a workaround for
+    // Safari (confirmed in version 4 on Windows). When removing the attribute
+    // without setting it to -1 first, the element remains keyboard focusable
+    // despite not having a tabIndex attribute anymore.
+    element.tabIndex = -1;
+    element.removeAttribute('tabIndex'); // Must be camelCase!
+  }
+};
+
+
+/**
+ * Returns true if the element can be focused, i.e. it has a tab index that
+ * allows it to receive keyboard focus (tabIndex >= 0), or it is an element
+ * that natively supports keyboard focus.
+ * @param {!Element} element Element to check.
+ * @return {boolean} Whether the element allows keyboard focus.
+ */
+goog.dom.isFocusable = function(element) {
+  var focusable;
+  // Some elements can have unspecified tab index and still receive focus.
+  if (goog.dom.nativelySupportsFocus_(element)) {
+    // Make sure the element is not disabled ...
+    focusable = !element.disabled &&
+        // ... and if a tab index is specified, it allows focus.
+        (!goog.dom.hasSpecifiedTabIndex_(element) ||
+         goog.dom.isTabIndexFocusable_(element));
+  } else {
+    focusable = goog.dom.isFocusableTabIndex(element);
+  }
+
+  // IE requires elements to be visible in order to focus them.
+  return focusable && goog.userAgent.IE ?
+             goog.dom.hasNonZeroBoundingRect_(element) : focusable;
+};
+
+
+/**
+ * Returns true if the element has a specified tab index.
+ * @param {!Element} element Element to check.
+ * @return {boolean} Whether the element has a specified tab index.
+ * @private
+ */
+goog.dom.hasSpecifiedTabIndex_ = function(element) {
+  // IE returns 0 for an unset tabIndex, so we must use getAttributeNode(),
+  // which returns an object with a 'specified' property if tabIndex is
+  // specified.  This works on other browsers, too.
+  var attrNode = element.getAttributeNode('tabindex'); // Must be lowercase!
+  return goog.isDefAndNotNull(attrNode) && attrNode.specified;
+};
+
+
+/**
+ * Returns true if the element's tab index allows the element to be focused.
+ * @param {!Element} element Element to check.
+ * @return {boolean} Whether the element's tab index allows focus.
+ * @private
+ */
+goog.dom.isTabIndexFocusable_ = function(element) {
+  var index = element.tabIndex;
+  // NOTE: IE9 puts tabIndex in 16-bit int, e.g. -2 is 65534.
+  return goog.isNumber(index) && index >= 0 && index < 32768;
+};
+
+
+/**
+ * Returns true if the element is focusable even when tabIndex is not set.
+ * @param {!Element} element Element to check.
+ * @return {boolean} Whether the element natively supports focus.
+ * @private
+ */
+goog.dom.nativelySupportsFocus_ = function(element) {
+  return element.tagName == goog.dom.TagName.A ||
+         element.tagName == goog.dom.TagName.INPUT ||
+         element.tagName == goog.dom.TagName.TEXTAREA ||
+         element.tagName == goog.dom.TagName.SELECT ||
+         element.tagName == goog.dom.TagName.BUTTON;
+};
+
+
+/**
+ * Returns true if the element has a bounding rectangle that would be visible
+ * (i.e. its width and height are greater than zero).
+ * @param {!Element} element Element to check.
+ * @return {boolean} Whether the element has a non-zero bounding rectangle.
+ * @private
+ */
+goog.dom.hasNonZeroBoundingRect_ = function(element) {
+  var rect = goog.isFunction(element['getBoundingClientRect']) ?
+      element.getBoundingClientRect() :
+      {'height': element.offsetHeight, 'width': element.offsetWidth};
+  return goog.isDefAndNotNull(rect) && rect.height > 0 && rect.width > 0;
+};
+
+
+/**
+ * Returns the text content of the current node, without markup and invisible
+ * symbols. New lines are stripped and whitespace is collapsed,
+ * such that each character would be visible.
+ *
+ * In browsers that support it, innerText is used.  Other browsers attempt to
+ * simulate it via node traversal.  Line breaks are canonicalized in IE.
+ *
+ * @param {Node} node The node from which we are getting content.
+ * @return {string} The text content.
+ */
+goog.dom.getTextContent = function(node) {
+  var textContent;
+  // Note(arv): IE9, Opera, and Safari 3 support innerText but they include
+  // text nodes in script tags. So we revert to use a user agent test here.
+  if (goog.dom.BrowserFeature.CAN_USE_INNER_TEXT && ('innerText' in node)) {
+    textContent = goog.string.canonicalizeNewlines(node.innerText);
+    // Unfortunately .innerText() returns text with &shy; symbols
+    // We need to filter it out and then remove duplicate whitespaces
+  } else {
+    var buf = [];
+    goog.dom.getTextContent_(node, buf, true);
+    textContent = buf.join('');
+  }
+
+  // Strip &shy; entities. goog.format.insertWordBreaks inserts them in Opera.
+  textContent = textContent.replace(/ \xAD /g, ' ').replace(/\xAD/g, '');
+  // Strip &#8203; entities. goog.format.insertWordBreaks inserts them in IE8.
+  textContent = textContent.replace(/\u200B/g, '');
+
+  // Skip this replacement on old browsers with working innerText, which
+  // automatically turns &nbsp; into ' ' and / +/ into ' ' when reading
+  // innerText.
+  if (!goog.dom.BrowserFeature.CAN_USE_INNER_TEXT) {
+    textContent = textContent.replace(/ +/g, ' ');
+  }
+  if (textContent != ' ') {
+    textContent = textContent.replace(/^\s*/, '');
+  }
+
+  return textContent;
+};
+
+
+/**
+ * Returns the text content of the current node, without markup.
+ *
+ * Unlike {@code getTextContent} this method does not collapse whitespaces
+ * or normalize lines breaks.
+ *
+ * @param {Node} node The node from which we are getting content.
+ * @return {string} The raw text content.
+ */
+goog.dom.getRawTextContent = function(node) {
+  var buf = [];
+  goog.dom.getTextContent_(node, buf, false);
+
+  return buf.join('');
+};
+
+
+/**
+ * Recursive support function for text content retrieval.
+ *
+ * @param {Node} node The node from which we are getting content.
+ * @param {Array<string>} buf string buffer.
+ * @param {boolean} normalizeWhitespace Whether to normalize whitespace.
+ * @private
+ */
+goog.dom.getTextContent_ = function(node, buf, normalizeWhitespace) {
+  if (node.nodeName in goog.dom.TAGS_TO_IGNORE_) {
+    // ignore certain tags
+  } else if (node.nodeType == goog.dom.NodeType.TEXT) {
+    if (normalizeWhitespace) {
+      buf.push(String(node.nodeValue).replace(/(\r\n|\r|\n)/g, ''));
+    } else {
+      buf.push(node.nodeValue);
+    }
+  } else if (node.nodeName in goog.dom.PREDEFINED_TAG_VALUES_) {
+    buf.push(goog.dom.PREDEFINED_TAG_VALUES_[node.nodeName]);
+  } else {
+    var child = node.firstChild;
+    while (child) {
+      goog.dom.getTextContent_(child, buf, normalizeWhitespace);
+      child = child.nextSibling;
+    }
+  }
+};
+
+
+/**
+ * Returns the text length of the text contained in a node, without markup. This
+ * is equivalent to the selection length if the node was selected, or the number
+ * of cursor movements to traverse the node. Images & BRs take one space.  New
+ * lines are ignored.
+ *
+ * @param {Node} node The node whose text content length is being calculated.
+ * @return {number} The length of {@code node}'s text content.
+ */
+goog.dom.getNodeTextLength = function(node) {
+  return goog.dom.getTextContent(node).length;
+};
+
+
+/**
+ * Returns the text offset of a node relative to one of its ancestors. The text
+ * length is the same as the length calculated by goog.dom.getNodeTextLength.
+ *
+ * @param {Node} node The node whose offset is being calculated.
+ * @param {Node=} opt_offsetParent The node relative to which the offset will
+ *     be calculated. Defaults to the node's owner document's body.
+ * @return {number} The text offset.
+ */
+goog.dom.getNodeTextOffset = function(node, opt_offsetParent) {
+  var root = opt_offsetParent || goog.dom.getOwnerDocument(node).body;
+  var buf = [];
+  while (node && node != root) {
+    var cur = node;
+    while ((cur = cur.previousSibling)) {
+      buf.unshift(goog.dom.getTextContent(cur));
+    }
+    node = node.parentNode;
+  }
+  // Trim left to deal with FF cases when there might be line breaks and empty
+  // nodes at the front of the text
+  return goog.string.trimLeft(buf.join('')).replace(/ +/g, ' ').length;
+};
+
+
+/**
+ * Returns the node at a given offset in a parent node.  If an object is
+ * provided for the optional third parameter, the node and the remainder of the
+ * offset will stored as properties of this object.
+ * @param {Node} parent The parent node.
+ * @param {number} offset The offset into the parent node.
+ * @param {Object=} opt_result Object to be used to store the return value. The
+ *     return value will be stored in the form {node: Node, remainder: number}
+ *     if this object is provided.
+ * @return {Node} The node at the given offset.
+ */
+goog.dom.getNodeAtOffset = function(parent, offset, opt_result) {
+  var stack = [parent], pos = 0, cur = null;
+  while (stack.length > 0 && pos < offset) {
+    cur = stack.pop();
+    if (cur.nodeName in goog.dom.TAGS_TO_IGNORE_) {
+      // ignore certain tags
+    } else if (cur.nodeType == goog.dom.NodeType.TEXT) {
+      var text = cur.nodeValue.replace(/(\r\n|\r|\n)/g, '').replace(/ +/g, ' ');
+      pos += text.length;
+    } else if (cur.nodeName in goog.dom.PREDEFINED_TAG_VALUES_) {
+      pos += goog.dom.PREDEFINED_TAG_VALUES_[cur.nodeName].length;
+    } else {
+      for (var i = cur.childNodes.length - 1; i >= 0; i--) {
+        stack.push(cur.childNodes[i]);
+      }
+    }
+  }
+  if (goog.isObject(opt_result)) {
+    opt_result.remainder = cur ? cur.nodeValue.length + offset - pos - 1 : 0;
+    opt_result.node = cur;
+  }
+
+  return cur;
+};
+
+
+/**
+ * Returns true if the object is a {@code NodeList}.  To qualify as a NodeList,
+ * the object must have a numeric length property and an item function (which
+ * has type 'string' on IE for some reason).
+ * @param {Object} val Object to test.
+ * @return {boolean} Whether the object is a NodeList.
+ */
+goog.dom.isNodeList = function(val) {
+  // TODO(attila): Now the isNodeList is part of goog.dom we can use
+  // goog.userAgent to make this simpler.
+  // A NodeList must have a length property of type 'number' on all platforms.
+  if (val && typeof val.length == 'number') {
+    // A NodeList is an object everywhere except Safari, where it's a function.
+    if (goog.isObject(val)) {
+      // A NodeList must have an item function (on non-IE platforms) or an item
+      // property of type 'string' (on IE).
+      return typeof val.item == 'function' || typeof val.item == 'string';
+    } else if (goog.isFunction(val)) {
+      // On Safari, a NodeList is a function with an item property that is also
+      // a function.
+      return typeof val.item == 'function';
+    }
+  }
+
+  // Not a NodeList.
+  return false;
+};
+
+
+/**
+ * Walks up the DOM hierarchy returning the first ancestor that has the passed
+ * tag name and/or class name. If the passed element matches the specified
+ * criteria, the element itself is returned.
+ * @param {Node} element The DOM node to start with.
+ * @param {?(goog.dom.TagName|string)=} opt_tag The tag name to match (or
+ *     null/undefined to match only based on class name).
+ * @param {?string=} opt_class The class name to match (or null/undefined to
+ *     match only based on tag name).
+ * @param {number=} opt_maxSearchSteps Maximum number of levels to search up the
+ *     dom.
+ * @return {Element} The first ancestor that matches the passed criteria, or
+ *     null if no match is found.
+ */
+goog.dom.getAncestorByTagNameAndClass = function(element, opt_tag, opt_class,
+    opt_maxSearchSteps) {
+  if (!opt_tag && !opt_class) {
+    return null;
+  }
+  var tagName = opt_tag ? opt_tag.toUpperCase() : null;
+  return /** @type {Element} */ (goog.dom.getAncestor(element,
+      function(node) {
+        return (!tagName || node.nodeName == tagName) &&
+               (!opt_class || goog.isString(node.className) &&
+                   goog.array.contains(node.className.split(/\s+/), opt_class));
+      }, true, opt_maxSearchSteps));
+};
+
+
+/**
+ * Walks up the DOM hierarchy returning the first ancestor that has the passed
+ * class name. If the passed element matches the specified criteria, the
+ * element itself is returned.
+ * @param {Node} element The DOM node to start with.
+ * @param {string} className The class name to match.
+ * @param {number=} opt_maxSearchSteps Maximum number of levels to search up the
+ *     dom.
+ * @return {Element} The first ancestor that matches the passed criteria, or
+ *     null if none match.
+ */
+goog.dom.getAncestorByClass = function(element, className, opt_maxSearchSteps) {
+  return goog.dom.getAncestorByTagNameAndClass(element, null, className,
+      opt_maxSearchSteps);
+};
+
+
+/**
+ * Walks up the DOM hierarchy returning the first ancestor that passes the
+ * matcher function.
+ * @param {Node} element The DOM node to start with.
+ * @param {function(Node) : boolean} matcher A function that returns true if the
+ *     passed node matches the desired criteria.
+ * @param {boolean=} opt_includeNode If true, the node itself is included in
+ *     the search (the first call to the matcher will pass startElement as
+ *     the node to test).
+ * @param {number=} opt_maxSearchSteps Maximum number of levels to search up the
+ *     dom.
+ * @return {Node} DOM node that matched the matcher, or null if there was
+ *     no match.
+ */
+goog.dom.getAncestor = function(
+    element, matcher, opt_includeNode, opt_maxSearchSteps) {
+  if (!opt_includeNode) {
+    element = element.parentNode;
+  }
+  var ignoreSearchSteps = opt_maxSearchSteps == null;
+  var steps = 0;
+  while (element && (ignoreSearchSteps || steps <= opt_maxSearchSteps)) {
+    goog.asserts.assert(element.name != 'parentNode');
+    if (matcher(element)) {
+      return element;
+    }
+    element = element.parentNode;
+    steps++;
+  }
+  // Reached the root of the DOM without a match
+  return null;
+};
+
+
+/**
+ * Determines the active element in the given document.
+ * @param {Document} doc The document to look in.
+ * @return {Element} The active element.
+ */
+goog.dom.getActiveElement = function(doc) {
+  try {
+    return doc && doc.activeElement;
+  } catch (e) {
+    // NOTE(nicksantos): Sometimes, evaluating document.activeElement in IE
+    // throws an exception. I'm not 100% sure why, but I suspect it chokes
+    // on document.activeElement if the activeElement has been recently
+    // removed from the DOM by a JS operation.
+    //
+    // We assume that an exception here simply means
+    // "there is no active element."
+  }
+
+  return null;
+};
+
+
+/**
+ * Gives the current devicePixelRatio.
+ *
+ * By default, this is the value of window.devicePixelRatio (which should be
+ * preferred if present).
+ *
+ * If window.devicePixelRatio is not present, the ratio is calculated with
+ * window.matchMedia, if present. Otherwise, gives 1.0.
+ *
+ * Some browsers (including Chrome) consider the browser zoom level in the pixel
+ * ratio, so the value may change across multiple calls.
+ *
+ * @return {number} The number of actual pixels per virtual pixel.
+ */
+goog.dom.getPixelRatio = function() {
+  var win = goog.dom.getWindow();
+
+  // devicePixelRatio does not work on Mobile firefox.
+  // TODO(user): Enable this check on a known working mobile Gecko version.
+  // Filed a bug: https://bugzilla.mozilla.org/show_bug.cgi?id=896804
+  var isFirefoxMobile = goog.userAgent.GECKO && goog.userAgent.MOBILE;
+
+  if (goog.isDef(win.devicePixelRatio) && !isFirefoxMobile) {
+    return win.devicePixelRatio;
+  } else if (win.matchMedia) {
+    return goog.dom.matchesPixelRatio_(.75) ||
+           goog.dom.matchesPixelRatio_(1.5) ||
+           goog.dom.matchesPixelRatio_(2) ||
+           goog.dom.matchesPixelRatio_(3) || 1;
+  }
+  return 1;
+};
+
+
+/**
+ * Calculates a mediaQuery to check if the current device supports the
+ * given actual to virtual pixel ratio.
+ * @param {number} pixelRatio The ratio of actual pixels to virtual pixels.
+ * @return {number} pixelRatio if applicable, otherwise 0.
+ * @private
+ */
+goog.dom.matchesPixelRatio_ = function(pixelRatio) {
+  var win = goog.dom.getWindow();
+  var query = ('(-webkit-min-device-pixel-ratio: ' + pixelRatio + '),' +
+               '(min--moz-device-pixel-ratio: ' + pixelRatio + '),' +
+               '(min-resolution: ' + pixelRatio + 'dppx)');
+  return win.matchMedia(query).matches ? pixelRatio : 0;
+};
+
+
+
+/**
+ * Create an instance of a DOM helper with a new document object.
+ * @param {Document=} opt_document Document object to associate with this
+ *     DOM helper.
+ * @constructor
+ */
+goog.dom.DomHelper = function(opt_document) {
+  /**
+   * Reference to the document object to use
+   * @type {!Document}
+   * @private
+   */
+  this.document_ = opt_document || goog.global.document || document;
+};
+
+
+/**
+ * Gets the dom helper object for the document where the element resides.
+ * @param {Node=} opt_node If present, gets the DomHelper for this node.
+ * @return {!goog.dom.DomHelper} The DomHelper.
+ */
+goog.dom.DomHelper.prototype.getDomHelper = goog.dom.getDomHelper;
+
+
+/**
+ * Sets the document object.
+ * @param {!Document} document Document object.
+ */
+goog.dom.DomHelper.prototype.setDocument = function(document) {
+  this.document_ = document;
+};
+
+
+/**
+ * Gets the document object being used by the dom library.
+ * @return {!Document} Document object.
+ */
+goog.dom.DomHelper.prototype.getDocument = function() {
+  return this.document_;
+};
+
+
+/**
+ * Alias for {@code getElementById}. If a DOM node is passed in then we just
+ * return that.
+ * @param {string|Element} element Element ID or a DOM node.
+ * @return {Element} The element with the given ID, or the node passed in.
+ */
+goog.dom.DomHelper.prototype.getElement = function(element) {
+  return goog.dom.getElementHelper_(this.document_, element);
+};
+
+
+/**
+ * Gets an element by id, asserting that the element is found.
+ *
+ * This is used when an element is expected to exist, and should fail with
+ * an assertion error if it does not (if assertions are enabled).
+ *
+ * @param {string} id Element ID.
+ * @return {!Element} The element with the given ID, if it exists.
+ */
+goog.dom.DomHelper.prototype.getRequiredElement = function(id) {
+  return goog.dom.getRequiredElementHelper_(this.document_, id);
+};
+
+
+/**
+ * Alias for {@code getElement}.
+ * @param {string|Element} element Element ID or a DOM node.
+ * @return {Element} The element with the given ID, or the node passed in.
+ * @deprecated Use {@link goog.dom.DomHelper.prototype.getElement} instead.
+ */
+goog.dom.DomHelper.prototype.$ = goog.dom.DomHelper.prototype.getElement;
+
+
+/**
+ * Looks up elements by both tag and class name, using browser native functions
+ * ({@code querySelectorAll}, {@code getElementsByTagName} or
+ * {@code getElementsByClassName}) where possible. The returned array is a live
+ * NodeList or a static list depending on the code path taken.
+ *
+ * @see goog.dom.query
+ *
+ * @param {?string=} opt_tag Element tag name or * for all tags.
+ * @param {?string=} opt_class Optional class name.
+ * @param {(Document|Element)=} opt_el Optional element to look in.
+ * @return { {length: number} } Array-like list of elements (only a length
+ *     property and numerical indices are guaranteed to exist).
+ */
+goog.dom.DomHelper.prototype.getElementsByTagNameAndClass = function(opt_tag,
+                                                                     opt_class,
+                                                                     opt_el) {
+  return goog.dom.getElementsByTagNameAndClass_(this.document_, opt_tag,
+                                                opt_class, opt_el);
+};
+
+
+/**
+ * Returns an array of all the elements with the provided className.
+ * @see {goog.dom.query}
+ * @param {string} className the name of the class to look for.
+ * @param {Element|Document=} opt_el Optional element to look in.
+ * @return { {length: number} } The items found with the class name provided.
+ */
+goog.dom.DomHelper.prototype.getElementsByClass = function(className, opt_el) {
+  var doc = opt_el || this.document_;
+  return goog.dom.getElementsByClass(className, doc);
+};
+
+
+/**
+ * Returns the first element we find matching the provided class name.
+ * @see {goog.dom.query}
+ * @param {string} className the name of the class to look for.
+ * @param {(Element|Document)=} opt_el Optional element to look in.
+ * @return {Element} The first item found with the class name provided.
+ */
+goog.dom.DomHelper.prototype.getElementByClass = function(className, opt_el) {
+  var doc = opt_el || this.document_;
+  return goog.dom.getElementByClass(className, doc);
+};
+
+
+/**
+ * Ensures an element with the given className exists, and then returns the
+ * first element with the provided className.
+ * @see {goog.dom.query}
+ * @param {string} className the name of the class to look for.
+ * @param {(!Element|!Document)=} opt_root Optional element or document to look
+ *     in.
+ * @return {!Element} The first item found with the class name provided.
+ * @throws {goog.asserts.AssertionError} Thrown if no element is found.
+ */
+goog.dom.DomHelper.prototype.getRequiredElementByClass = function(className,
+                                                                  opt_root) {
+  var root = opt_root || this.document_;
+  return goog.dom.getRequiredElementByClass(className, root);
+};
+
+
+/**
+ * Alias for {@code getElementsByTagNameAndClass}.
+ * @deprecated Use DomHelper getElementsByTagNameAndClass.
+ * @see goog.dom.query
+ *
+ * @param {?string=} opt_tag Element tag name.
+ * @param {?string=} opt_class Optional class name.
+ * @param {Element=} opt_el Optional element to look in.
+ * @return { {length: number} } Array-like list of elements (only a length
+ *     property and numerical indices are guaranteed to exist).
+ */
+goog.dom.DomHelper.prototype.$$ =
+    goog.dom.DomHelper.prototype.getElementsByTagNameAndClass;
+
+
+/**
+ * Sets a number of properties on a node.
+ * @param {Element} element DOM node to set properties on.
+ * @param {Object} properties Hash of property:value pairs.
+ */
+goog.dom.DomHelper.prototype.setProperties = goog.dom.setProperties;
+
+
+/**
+ * Gets the dimensions of the viewport.
+ * @param {Window=} opt_window Optional window element to test. Defaults to
+ *     the window of the Dom Helper.
+ * @return {!goog.math.Size} Object with values 'width' and 'height'.
+ */
+goog.dom.DomHelper.prototype.getViewportSize = function(opt_window) {
+  // TODO(arv): This should not take an argument. That breaks the rule of a
+  // a DomHelper representing a single frame/window/document.
+  return goog.dom.getViewportSize(opt_window || this.getWindow());
+};
+
+
+/**
+ * Calculates the height of the document.
+ *
+ * @return {number} The height of the document.
+ */
+goog.dom.DomHelper.prototype.getDocumentHeight = function() {
+  return goog.dom.getDocumentHeight_(this.getWindow());
+};
+
+
+/**
+ * Typedef for use with goog.dom.createDom and goog.dom.append.
+ * @typedef {Object|string|Array|NodeList}
+ */
+goog.dom.Appendable;
+
+
+/**
+ * Returns a dom node with a set of attributes.  This function accepts varargs
+ * for subsequent nodes to be added.  Subsequent nodes will be added to the
+ * first node as childNodes.
+ *
+ * So:
+ * <code>createDom('div', null, createDom('p'), createDom('p'));</code>
+ * would return a div with two child paragraphs
+ *
+ * An easy way to move all child nodes of an existing element to a new parent
+ * element is:
+ * <code>createDom('div', null, oldElement.childNodes);</code>
+ * which will remove all child nodes from the old element and add them as
+ * child nodes of the new DIV.
+ *
+ * @param {string} tagName Tag to create.
+ * @param {Object|string=} opt_attributes If object, then a map of name-value
+ *     pairs for attributes. If a string, then this is the className of the new
+ *     element.
+ * @param {...goog.dom.Appendable} var_args Further DOM nodes or
+ *     strings for text nodes. If one of the var_args is an array or
+ *     NodeList, its elements will be added as childNodes instead.
+ * @return {!Element} Reference to a DOM node.
+ */
+goog.dom.DomHelper.prototype.createDom = function(tagName,
+                                                  opt_attributes,
+                                                  var_args) {
+  return goog.dom.createDom_(this.document_, arguments);
+};
+
+
+/**
+ * Alias for {@code createDom}.
+ * @param {string} tagName Tag to create.
+ * @param {(Object|string)=} opt_attributes If object, then a map of name-value
+ *     pairs for attributes. If a string, then this is the className of the new
+ *     element.
+ * @param {...goog.dom.Appendable} var_args Further DOM nodes or strings for
+ *     text nodes.  If one of the var_args is an array, its children will be
+ *     added as childNodes instead.
+ * @return {!Element} Reference to a DOM node.
+ * @deprecated Use {@link goog.dom.DomHelper.prototype.createDom} instead.
+ */
+goog.dom.DomHelper.prototype.$dom = goog.dom.DomHelper.prototype.createDom;
+
+
+/**
+ * Creates a new element.
+ * @param {string} name Tag name.
+ * @return {!Element} The new element.
+ */
+goog.dom.DomHelper.prototype.createElement = function(name) {
+  return this.document_.createElement(name);
+};
+
+
+/**
+ * Creates a new text node.
+ * @param {number|string} content Content.
+ * @return {!Text} The new text node.
+ */
+goog.dom.DomHelper.prototype.createTextNode = function(content) {
+  return this.document_.createTextNode(String(content));
+};
+
+
+/**
+ * Create a table.
+ * @param {number} rows The number of rows in the table.  Must be >= 1.
+ * @param {number} columns The number of columns in the table.  Must be >= 1.
+ * @param {boolean=} opt_fillWithNbsp If true, fills table entries with
+ *     {@code goog.string.Unicode.NBSP} characters.
+ * @return {!HTMLElement} The created table.
+ */
+goog.dom.DomHelper.prototype.createTable = function(rows, columns,
+    opt_fillWithNbsp) {
+  return goog.dom.createTable_(this.document_, rows, columns,
+      !!opt_fillWithNbsp);
+};
+
+
+/**
+ * Converts an HTML into a node or a document fragment. A single Node is used if
+ * {@code html} only generates a single node. If {@code html} generates multiple
+ * nodes then these are put inside a {@code DocumentFragment}.
+ * @param {!goog.html.SafeHtml} html The HTML markup to convert.
+ * @return {!Node} The resulting node.
+ */
+goog.dom.DomHelper.prototype.safeHtmlToNode = function(html) {
+  return goog.dom.safeHtmlToNode_(this.document_, html);
+};
+
+
+/**
+ * Converts an HTML string into a node or a document fragment.  A single Node
+ * is used if the {@code htmlString} only generates a single node.  If the
+ * {@code htmlString} generates multiple nodes then these are put inside a
+ * {@code DocumentFragment}.
+ *
+ * @param {string} htmlString The HTML string to convert.
+ * @return {!Node} The resulting node.
+ */
+goog.dom.DomHelper.prototype.htmlToDocumentFragment = function(htmlString) {
+  return goog.dom.htmlToDocumentFragment_(this.document_, htmlString);
+};
+
+
+/**
+ * Returns true if the browser is in "CSS1-compatible" (standards-compliant)
+ * mode, false otherwise.
+ * @return {boolean} True if in CSS1-compatible mode.
+ */
+goog.dom.DomHelper.prototype.isCss1CompatMode = function() {
+  return goog.dom.isCss1CompatMode_(this.document_);
+};
+
+
+/**
+ * Gets the window object associated with the document.
+ * @return {!Window} The window associated with the given document.
+ */
+goog.dom.DomHelper.prototype.getWindow = function() {
+  return goog.dom.getWindow_(this.document_);
+};
+
+
+/**
+ * Gets the document scroll element.
+ * @return {!Element} Scrolling element.
+ */
+goog.dom.DomHelper.prototype.getDocumentScrollElement = function() {
+  return goog.dom.getDocumentScrollElement_(this.document_);
+};
+
+
+/**
+ * Gets the document scroll distance as a coordinate object.
+ * @return {!goog.math.Coordinate} Object with properties 'x' and 'y'.
+ */
+goog.dom.DomHelper.prototype.getDocumentScroll = function() {
+  return goog.dom.getDocumentScroll_(this.document_);
+};
+
+
+/**
+ * Determines the active element in the given document.
+ * @param {Document=} opt_doc The document to look in.
+ * @return {Element} The active element.
+ */
+goog.dom.DomHelper.prototype.getActiveElement = function(opt_doc) {
+  return goog.dom.getActiveElement(opt_doc || this.document_);
+};
+
+
+/**
+ * Appends a child to a node.
+ * @param {Node} parent Parent.
+ * @param {Node} child Child.
+ */
+goog.dom.DomHelper.prototype.appendChild = goog.dom.appendChild;
+
+
+/**
+ * Appends a node with text or other nodes.
+ * @param {!Node} parent The node to append nodes to.
+ * @param {...goog.dom.Appendable} var_args The things to append to the node.
+ *     If this is a Node it is appended as is.
+ *     If this is a string then a text node is appended.
+ *     If this is an array like object then fields 0 to length - 1 are appended.
+ */
+goog.dom.DomHelper.prototype.append = goog.dom.append;
+
+
+/**
+ * Determines if the given node can contain children, intended to be used for
+ * HTML generation.
+ *
+ * @param {Node} node The node to check.
+ * @return {boolean} Whether the node can contain children.
+ */
+goog.dom.DomHelper.prototype.canHaveChildren = goog.dom.canHaveChildren;
+
+
+/**
+ * Removes all the child nodes on a DOM node.
+ * @param {Node} node Node to remove children from.
+ */
+goog.dom.DomHelper.prototype.removeChildren = goog.dom.removeChildren;
+
+
+/**
+ * Inserts a new node before an existing reference node (i.e., as the previous
+ * sibling). If the reference node has no parent, then does nothing.
+ * @param {Node} newNode Node to insert.
+ * @param {Node} refNode Reference node to insert before.
+ */
+goog.dom.DomHelper.prototype.insertSiblingBefore = goog.dom.insertSiblingBefore;
+
+
+/**
+ * Inserts a new node after an existing reference node (i.e., as the next
+ * sibling). If the reference node has no parent, then does nothing.
+ * @param {Node} newNode Node to insert.
+ * @param {Node} refNode Reference node to insert after.
+ */
+goog.dom.DomHelper.prototype.insertSiblingAfter = goog.dom.insertSiblingAfter;
+
+
+/**
+ * Insert a child at a given index. If index is larger than the number of child
+ * nodes that the parent currently has, the node is inserted as the last child


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