// v0.4.4 - https://github.com/mozilla/readability/commit/49d345a455da1f4aa93f8b41e0f50422f9959c7c

/*
 * Copyright (c) 2010 Arc90 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
 *
 *     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.
 */

/*
 * This code is heavily based on Arc90's readability.js (1.7.1) script
 * available at: http://code.google.com/p/arc90labs-readability
 */

/**
 * Public constructor.
 * @param {HTMLDocument} doc     The document to parse.
 * @param {Object}       options The options object.
 */
function Readability(doc, options) {
	// In some older versions, people passed a URI as the first argument. Cope:
	if (options && options.documentElement) {
	  doc = options;
	  options = arguments[2];
	} else if (!doc || !doc.documentElement) {
	  throw new Error("First argument to Readability constructor should be a document object.");
	}
	options = options || {};
  
	this._doc = doc;
	this._docJSDOMParser = this._doc.firstChild.__JSDOMParser__;
	this._articleTitle = null;
	this._articleByline = null;
	this._articleDir = null;
	this._articleSiteName = null;
	this._attempts = [];
  
	// Configurable options
	this._debug = !!options.debug;
	this._maxElemsToParse = options.maxElemsToParse || this.DEFAULT_MAX_ELEMS_TO_PARSE;
	this._nbTopCandidates = options.nbTopCandidates || this.DEFAULT_N_TOP_CANDIDATES;
	this._charThreshold = options.charThreshold || this.DEFAULT_CHAR_THRESHOLD;
	this._classesToPreserve = this.CLASSES_TO_PRESERVE.concat(options.classesToPreserve || []);
	this._keepClasses = !!options.keepClasses;
	this._serializer = options.serializer || function(el) {
	  return el.innerHTML;
	};
	this._disableJSONLD = !!options.disableJSONLD;
	this._allowedVideoRegex = options.allowedVideoRegex || this.REGEXPS.videos;
  
	// Start with all flags set
	this._flags = this.FLAG_STRIP_UNLIKELYS |
				  this.FLAG_WEIGHT_CLASSES |
				  this.FLAG_CLEAN_CONDITIONALLY;
  
  
	// Control whether log messages are sent to the console
	if (this._debug) {
	  let logNode = function(node) {
		if (node.nodeType == node.TEXT_NODE) {
		  return `${node.nodeName} ("${node.textContent}")`;
		}
		let attrPairs = Array.from(node.attributes || [], function(attr) {
		  return `${attr.name}="${attr.value}"`;
		}).join(" ");
		return `<${node.localName} ${attrPairs}>`;
	  };
	  this.log = function () {
		if (typeof console !== "undefined") {
		  let args = Array.from(arguments, arg => {
			if (arg && arg.nodeType == this.ELEMENT_NODE) {
			  return logNode(arg);
			}
			return arg;
		  });
		  args.unshift("Reader: (Readability)");
		  console.log.apply(console, args);
		} else if (typeof dump !== "undefined") {
		  /* global dump */
		  var msg = Array.prototype.map.call(arguments, function(x) {
			return (x && x.nodeName) ? logNode(x) : x;
		  }).join(" ");
		  dump("Reader: (Readability) " + msg + "\n");
		}
	  };
	} else {
	  this.log = function () {};
	}
  }
  
  Readability.prototype = {
	FLAG_STRIP_UNLIKELYS: 0x1,
	FLAG_WEIGHT_CLASSES: 0x2,
	FLAG_CLEAN_CONDITIONALLY: 0x4,
  
	// https://developer.mozilla.org/en-US/docs/Web/API/Node/nodeType
	ELEMENT_NODE: 1,
	TEXT_NODE: 3,
  
	// Max number of nodes supported by this parser. Default: 0 (no limit)
	DEFAULT_MAX_ELEMS_TO_PARSE: 0,
  
	// The number of top candidates to consider when analysing how
	// tight the competition is among candidates.
	DEFAULT_N_TOP_CANDIDATES: 5,
  
	// Element tags to score by default.
	DEFAULT_TAGS_TO_SCORE: "section,h2,h3,h4,h5,h6,p,td,pre".toUpperCase().split(","),
  
	// The default number of chars an article must have in order to return a result
	DEFAULT_CHAR_THRESHOLD: 500,
  
	// All of the regular expressions in use within readability.
	// Defined up here so we don't instantiate them repeatedly in loops.
	REGEXPS: {
	  // NOTE: These two regular expressions are duplicated in
	  // Readability-readerable.js. Please keep both copies in sync.
	  unlikelyCandidates: /-ad-|ai2html|banner|breadcrumbs|combx|comment|community|cover-wrap|disqus|extra|footer|gdpr|header|legends|menu|related|remark|replies|rss|shoutbox|sidebar|skyscraper|social|sponsor|supplemental|ad-break|agegate|pagination|pager|popup|yom-remote/i,
	  okMaybeItsACandidate: /and|article|body|column|content|main|shadow/i,
  
	  positive: /article|body|content|entry|hentry|h-entry|main|page|pagination|post|text|blog|story/i,
	  negative: /-ad-|hidden|^hid$| hid$| hid |^hid |banner|combx|comment|com-|contact|foot|footer|footnote|gdpr|masthead|media|meta|outbrain|promo|related|scroll|share|shoutbox|sidebar|skyscraper|sponsor|shopping|tags|tool|widget/i,
	  extraneous: /print|archive|comment|discuss|e[\-]?mail|share|reply|all|login|sign|single|utility/i,
	  byline: /byline|author|dateline|writtenby|p-author/i,
	  replaceFonts: /<(\/?)font[^>]*>/gi,
	  normalize: /\s{2,}/g,
	  videos: /\/\/(www\.)?((dailymotion|youtube|youtube-nocookie|player\.vimeo|v\.qq)\.com|(archive|upload\.wikimedia)\.org|player\.twitch\.tv)/i,
	  shareElements: /(\b|_)(share|sharedaddy)(\b|_)/i,
	  nextLink: /(next|weiter|continue|>([^\|]|$)|»([^\|]|$))/i,
	  prevLink: /(prev|earl|old|new|<|«)/i,
	  tokenize: /\W+/g,
	  whitespace: /^\s*$/,
	  hasContent: /\S$/,
	  hashUrl: /^#.+/,
	  srcsetUrl: /(\S+)(\s+[\d.]+[xw])?(\s*(?:,|$))/g,
	  b64DataUrl: /^data:\s*([^\s;,]+)\s*;\s*base64\s*,/i,
	  // Commas as used in Latin, Sindhi, Chinese and various other scripts.
	  // see: https://en.wikipedia.org/wiki/Comma#Comma_variants
	  commas: /\u002C|\u060C|\uFE50|\uFE10|\uFE11|\u2E41|\u2E34|\u2E32|\uFF0C/g,
	  // See: https://schema.org/Article
	  jsonLdArticleTypes: /^Article|AdvertiserContentArticle|NewsArticle|AnalysisNewsArticle|AskPublicNewsArticle|BackgroundNewsArticle|OpinionNewsArticle|ReportageNewsArticle|ReviewNewsArticle|Report|SatiricalArticle|ScholarlyArticle|MedicalScholarlyArticle|SocialMediaPosting|BlogPosting|LiveBlogPosting|DiscussionForumPosting|TechArticle|APIReference$/
	},
  
	UNLIKELY_ROLES: [ "menu", "menubar", "complementary", "navigation", "alert", "alertdialog", "dialog" ],
  
	DIV_TO_P_ELEMS: new Set([ "BLOCKQUOTE", "DL", "DIV", "IMG", "OL", "P", "PRE", "TABLE", "UL" ]),
  
	ALTER_TO_DIV_EXCEPTIONS: ["DIV", "ARTICLE", "SECTION", "P"],
  
	PRESENTATIONAL_ATTRIBUTES: [ "align", "background", "bgcolor", "border", "cellpadding", "cellspacing", "frame", "hspace", "rules", "style", "valign", "vspace" ],
  
	DEPRECATED_SIZE_ATTRIBUTE_ELEMS: [ "TABLE", "TH", "TD", "HR", "PRE" ],
  
	// The commented out elements qualify as phrasing content but tend to be
	// removed by readability when put into paragraphs, so we ignore them here.
	PHRASING_ELEMS: [
	  // "CANVAS", "IFRAME", "SVG", "VIDEO",
	  "ABBR", "AUDIO", "B", "BDO", "BR", "BUTTON", "CITE", "CODE", "DATA",
	  "DATALIST", "DFN", "EM", "EMBED", "I", "IMG", "INPUT", "KBD", "LABEL",
	  "MARK", "MATH", "METER", "NOSCRIPT", "OBJECT", "OUTPUT", "PROGRESS", "Q",
	  "RUBY", "SAMP", "SCRIPT", "SELECT", "SMALL", "SPAN", "STRONG", "SUB",
	  "SUP", "TEXTAREA", "TIME", "VAR", "WBR"
	],
  
	// These are the classes that readability sets itself.
	CLASSES_TO_PRESERVE: [ "page" ],
  
	// These are the list of HTML entities that need to be escaped.
	HTML_ESCAPE_MAP: {
	  "lt": "<",
	  "gt": ">",
	  "amp": "&",
	  "quot": '"',
	  "apos": "'",
	},
  
	/**
	 * Run any post-process modifications to article content as necessary.
	 *
	 * @param Element
	 * @return void
	**/
	_postProcessContent: function(articleContent) {
	  // Readability cannot open relative uris so we convert them to absolute uris.
	  this._fixRelativeUris(articleContent);
  
	  this._simplifyNestedElements(articleContent);
  
	  if (!this._keepClasses) {
		// Remove classes.
		this._cleanClasses(articleContent);
	  }
	},
  
	/**
	 * Iterates over a NodeList, calls `filterFn` for each node and removes node
	 * if function returned `true`.
	 *
	 * If function is not passed, removes all the nodes in node list.
	 *
	 * @param NodeList nodeList The nodes to operate on
	 * @param Function filterFn the function to use as a filter
	 * @return void
	 */
	_removeNodes: function(nodeList, filterFn) {
	  // Avoid ever operating on live node lists.
	  if (this._docJSDOMParser && nodeList._isLiveNodeList) {
		throw new Error("Do not pass live node lists to _removeNodes");
	  }
	  for (var i = nodeList.length - 1; i >= 0; i--) {
		var node = nodeList[i];
		var parentNode = node.parentNode;
		if (parentNode) {
		  if (!filterFn || filterFn.call(this, node, i, nodeList)) {
			parentNode.removeChild(node);
		  }
		}
	  }
	},
  
	/**
	 * Iterates over a NodeList, and calls _setNodeTag for each node.
	 *
	 * @param NodeList nodeList The nodes to operate on
	 * @param String newTagName the new tag name to use
	 * @return void
	 */
	_replaceNodeTags: function(nodeList, newTagName) {
	  // Avoid ever operating on live node lists.
	  if (this._docJSDOMParser && nodeList._isLiveNodeList) {
		throw new Error("Do not pass live node lists to _replaceNodeTags");
	  }
	  for (const node of nodeList) {
		this._setNodeTag(node, newTagName);
	  }
	},
  
	/**
	 * Iterate over a NodeList, which doesn't natively fully implement the Array
	 * interface.
	 *
	 * For convenience, the current object context is applied to the provided
	 * iterate function.
	 *
	 * @param  NodeList nodeList The NodeList.
	 * @param  Function fn       The iterate function.
	 * @return void
	 */
	_forEachNode: function(nodeList, fn) {
	  Array.prototype.forEach.call(nodeList, fn, this);
	},
  
	/**
	 * Iterate over a NodeList, and return the first node that passes
	 * the supplied test function
	 *
	 * For convenience, the current object context is applied to the provided
	 * test function.
	 *
	 * @param  NodeList nodeList The NodeList.
	 * @param  Function fn       The test function.
	 * @return void
	 */
	_findNode: function(nodeList, fn) {
	  return Array.prototype.find.call(nodeList, fn, this);
	},
  
	/**
	 * Iterate over a NodeList, return true if any of the provided iterate
	 * function calls returns true, false otherwise.
	 *
	 * For convenience, the current object context is applied to the
	 * provided iterate function.
	 *
	 * @param  NodeList nodeList The NodeList.
	 * @param  Function fn       The iterate function.
	 * @return Boolean
	 */
	_someNode: function(nodeList, fn) {
	  return Array.prototype.some.call(nodeList, fn, this);
	},
  
	/**
	 * Iterate over a NodeList, return true if all of the provided iterate
	 * function calls return true, false otherwise.
	 *
	 * For convenience, the current object context is applied to the
	 * provided iterate function.
	 *
	 * @param  NodeList nodeList The NodeList.
	 * @param  Function fn       The iterate function.
	 * @return Boolean
	 */
	_everyNode: function(nodeList, fn) {
	  return Array.prototype.every.call(nodeList, fn, this);
	},
  
	/**
	 * Concat all nodelists passed as arguments.
	 *
	 * @return ...NodeList
	 * @return Array
	 */
	_concatNodeLists: function() {
	  var slice = Array.prototype.slice;
	  var args = slice.call(arguments);
	  var nodeLists = args.map(function(list) {
		return slice.call(list);
	  });
	  return Array.prototype.concat.apply([], nodeLists);
	},
  
	_getAllNodesWithTag: function(node, tagNames) {
	  if (node.querySelectorAll) {
		return node.querySelectorAll(tagNames.join(","));
	  }
	  return [].concat.apply([], tagNames.map(function(tag) {
		var collection = node.getElementsByTagName(tag);
		return Array.isArray(collection) ? collection : Array.from(collection);
	  }));
	},
  
	/**
	 * Removes the class="" attribute from every element in the given
	 * subtree, except those that match CLASSES_TO_PRESERVE and
	 * the classesToPreserve array from the options object.
	 *
	 * @param Element
	 * @return void
	 */
	_cleanClasses: function(node) {
	  var classesToPreserve = this._classesToPreserve;
	  var className = (node.getAttribute("class") || "")
		.split(/\s+/)
		.filter(function(cls) {
		  return classesToPreserve.indexOf(cls) != -1;
		})
		.join(" ");
  
	  if (className) {
		node.setAttribute("class", className);
	  } else {
		node.removeAttribute("class");
	  }
  
	  for (node = node.firstElementChild; node; node = node.nextElementSibling) {
		this._cleanClasses(node);
	  }
	},
  
	/**
	 * Converts each <a> and <img> uri in the given element to an absolute URI,
	 * ignoring #ref URIs.
	 *
	 * @param Element
	 * @return void
	 */
	_fixRelativeUris: function(articleContent) {
	  var baseURI = this._doc.baseURI;
	  var documentURI = this._doc.documentURI;
	  function toAbsoluteURI(uri) {
		// Leave hash links alone if the base URI matches the document URI:
		if (baseURI == documentURI && uri.charAt(0) == "#") {
		  return uri;
		}
  
		// Otherwise, resolve against base URI:
		try {
		  return new URL(uri, baseURI).href;
		} catch (ex) {
		  // Something went wrong, just return the original:
		}
		return uri;
	  }
  
	  var links = this._getAllNodesWithTag(articleContent, ["a"]);
	  this._forEachNode(links, function(link) {
		var href = link.getAttribute("href");
		if (href) {
		  // Remove links with javascript: URIs, since
		  // they won't work after scripts have been removed from the page.
		  if (href.indexOf("javascript:") === 0) {
			// if the link only contains simple text content, it can be converted to a text node
			if (link.childNodes.length === 1 && link.childNodes[0].nodeType === this.TEXT_NODE) {
			  var text = this._doc.createTextNode(link.textContent);
			  link.parentNode.replaceChild(text, link);
			} else {
			  // if the link has multiple children, they should all be preserved
			  var container = this._doc.createElement("span");
			  while (link.firstChild) {
				container.appendChild(link.firstChild);
			  }
			  link.parentNode.replaceChild(container, link);
			}
		  } else {
			link.setAttribute("href", toAbsoluteURI(href));
		  }
		}
	  });
  
	  var medias = this._getAllNodesWithTag(articleContent, [
		"img", "picture", "figure", "video", "audio", "source"
	  ]);
  
	  this._forEachNode(medias, function(media) {
		var src = media.getAttribute("src");
		var poster = media.getAttribute("poster");
		var srcset = media.getAttribute("srcset");
  
		if (src) {
		  media.setAttribute("src", toAbsoluteURI(src));
		}
  
		if (poster) {
		  media.setAttribute("poster", toAbsoluteURI(poster));
		}
  
		if (srcset) {
		  var newSrcset = srcset.replace(this.REGEXPS.srcsetUrl, function(_, p1, p2, p3) {
			return toAbsoluteURI(p1) + (p2 || "") + p3;
		  });
  
		  media.setAttribute("srcset", newSrcset);
		}
	  });
	},
  
	_simplifyNestedElements: function(articleContent) {
	  var node = articleContent;
  
	  while (node) {
		if (node.parentNode && ["DIV", "SECTION"].includes(node.tagName) && !(node.id && node.id.startsWith("readability"))) {
		  if (this._isElementWithoutContent(node)) {
			node = this._removeAndGetNext(node);
			continue;
		  } else if (this._hasSingleTagInsideElement(node, "DIV") || this._hasSingleTagInsideElement(node, "SECTION")) {
			var child = node.children[0];
			for (var i = 0; i < node.attributes.length; i++) {
			  child.setAttribute(node.attributes[i].name, node.attributes[i].value);
			}
			node.parentNode.replaceChild(child, node);
			node = child;
			continue;
		  }
		}
  
		node = this._getNextNode(node);
	  }
	},
  
	/**
	 * Get the article title as an H1.
	 *
	 * @return string
	 **/
	_getArticleTitle: function() {
	  var doc = this._doc;
	  var curTitle = "";
	  var origTitle = "";
  
	  try {
		curTitle = origTitle = doc.title.trim();
  
		// If they had an element with id "title" in their HTML
		if (typeof curTitle !== "string")
		  curTitle = origTitle = this._getInnerText(doc.getElementsByTagName("title")[0]);
	  } catch (e) {/* ignore exceptions setting the title. */}
  
	  var titleHadHierarchicalSeparators = false;
	  function wordCount(str) {
		return str.split(/\s+/).length;
	  }
  
	  // If there's a separator in the title, first remove the final part
	  if ((/ [\|\-\\\/>»] /).test(curTitle)) {
		titleHadHierarchicalSeparators = / [\\\/>»] /.test(curTitle);
		curTitle = origTitle.replace(/(.*)[\|\-\\\/>»] .*/gi, "$1");
  
		// If the resulting title is too short (3 words or fewer), remove
		// the first part instead:
		if (wordCount(curTitle) < 3)
		  curTitle = origTitle.replace(/[^\|\-\\\/>»]*[\|\-\\\/>»](.*)/gi, "$1");
	  } else if (curTitle.indexOf(": ") !== -1) {
		// Check if we have an heading containing this exact string, so we
		// could assume it's the full title.
		var headings = this._concatNodeLists(
		  doc.getElementsByTagName("h1"),
		  doc.getElementsByTagName("h2")
		);
		var trimmedTitle = curTitle.trim();
		var match = this._someNode(headings, function(heading) {
		  return heading.textContent.trim() === trimmedTitle;
		});
  
		// If we don't, let's extract the title out of the original title string.
		if (!match) {
		  curTitle = origTitle.substring(origTitle.lastIndexOf(":") + 1);
  
		  // If the title is now too short, try the first colon instead:
		  if (wordCount(curTitle) < 3) {
			curTitle = origTitle.substring(origTitle.indexOf(":") + 1);
			// But if we have too many words before the colon there's something weird
			// with the titles and the H tags so let's just use the original title instead
		  } else if (wordCount(origTitle.substr(0, origTitle.indexOf(":"))) > 5) {
			curTitle = origTitle;
		  }
		}
	  } else if (curTitle.length > 150 || curTitle.length < 15) {
		var hOnes = doc.getElementsByTagName("h1");
  
		if (hOnes.length === 1)
		  curTitle = this._getInnerText(hOnes[0]);
	  }
  
	  curTitle = curTitle.trim().replace(this.REGEXPS.normalize, " ");
	  // If we now have 4 words or fewer as our title, and either no
	  // 'hierarchical' separators (\, /, > or ») were found in the original
	  // title or we decreased the number of words by more than 1 word, use
	  // the original title.
	  var curTitleWordCount = wordCount(curTitle);
	  if (curTitleWordCount <= 4 &&
		  (!titleHadHierarchicalSeparators ||
		   curTitleWordCount != wordCount(origTitle.replace(/[\|\-\\\/>»]+/g, "")) - 1)) {
		curTitle = origTitle;
	  }
  
	  return curTitle;
	},
  
	/**
	 * Prepare the HTML document for readability to scrape it.
	 * This includes things like stripping javascript, CSS, and handling terrible markup.
	 *
	 * @return void
	 **/
	_prepDocument: function() {
	  var doc = this._doc;
  
	  // Remove all style tags in head
	  this._removeNodes(this._getAllNodesWithTag(doc, ["style"]));
  
	  if (doc.body) {
		this._replaceBrs(doc.body);
	  }
  
	  this._replaceNodeTags(this._getAllNodesWithTag(doc, ["font"]), "SPAN");
	},
  
	/**
	 * Finds the next node, starting from the given node, and ignoring
	 * whitespace in between. If the given node is an element, the same node is
	 * returned.
	 */
	_nextNode: function (node) {
	  var next = node;
	  while (next
		  && (next.nodeType != this.ELEMENT_NODE)
		  && this.REGEXPS.whitespace.test(next.textContent)) {
		next = next.nextSibling;
	  }
	  return next;
	},
  
	/**
	 * Replaces 2 or more successive <br> elements with a single <p>.
	 * Whitespace between <br> elements are ignored. For example:
	 *   <div>foo<br>bar<br> <br><br>abc</div>
	 * will become:
	 *   <div>foo<br>bar<p>abc</p></div>
	 */
	_replaceBrs: function (elem) {
	  this._forEachNode(this._getAllNodesWithTag(elem, ["br"]), function(br) {
		var next = br.nextSibling;
  
		// Whether 2 or more <br> elements have been found and replaced with a
		// <p> block.
		var replaced = false;
  
		// If we find a <br> chain, remove the <br>s until we hit another node
		// or non-whitespace. This leaves behind the first <br> in the chain
		// (which will be replaced with a <p> later).
		while ((next = this._nextNode(next)) && (next.tagName == "BR")) {
		  replaced = true;
		  var brSibling = next.nextSibling;
		  next.parentNode.removeChild(next);
		  next = brSibling;
		}
  
		// If we removed a <br> chain, replace the remaining <br> with a <p>. Add
		// all sibling nodes as children of the <p> until we hit another <br>
		// chain.
		if (replaced) {
		  var p = this._doc.createElement("p");
		  br.parentNode.replaceChild(p, br);
  
		  next = p.nextSibling;
		  while (next) {
			// If we've hit another <br><br>, we're done adding children to this <p>.
			if (next.tagName == "BR") {
			  var nextElem = this._nextNode(next.nextSibling);
			  if (nextElem && nextElem.tagName == "BR")
				break;
			}
  
			if (!this._isPhrasingContent(next))
			  break;
  
			// Otherwise, make this node a child of the new <p>.
			var sibling = next.nextSibling;
			p.appendChild(next);
			next = sibling;
		  }
  
		  while (p.lastChild && this._isWhitespace(p.lastChild)) {
			p.removeChild(p.lastChild);
		  }
  
		  if (p.parentNode.tagName === "P")
			this._setNodeTag(p.parentNode, "DIV");
		}
	  });
	},
  
	_setNodeTag: function (node, tag) {
	  this.log("_setNodeTag", node, tag);
	  if (this._docJSDOMParser) {
		node.localName = tag.toLowerCase();
		node.tagName = tag.toUpperCase();
		return node;
	  }
  
	  var replacement = node.ownerDocument.createElement(tag);
	  while (node.firstChild) {
		replacement.appendChild(node.firstChild);
	  }
	  node.parentNode.replaceChild(replacement, node);
	  if (node.readability)
		replacement.readability = node.readability;
  
	  for (var i = 0; i < node.attributes.length; i++) {
		try {
		  replacement.setAttribute(node.attributes[i].name, node.attributes[i].value);
		} catch (ex) {
		  /* it's possible for setAttribute() to throw if the attribute name
		   * isn't a valid XML Name. Such attributes can however be parsed from
		   * source in HTML docs, see https://github.com/whatwg/html/issues/4275,
		   * so we can hit them here and then throw. We don't care about such
		   * attributes so we ignore them.
		   */
		}
	  }
	  return replacement;
	},
  
	/**
	 * Prepare the article node for display. Clean out any inline styles,
	 * iframes, forms, strip extraneous <p> tags, etc.
	 *
	 * @param Element
	 * @return void
	 **/
	_prepArticle: function(articleContent) {
	  this._cleanStyles(articleContent);
  
	  // Check for data tables before we continue, to avoid removing items in
	  // those tables, which will often be isolated even though they're
	  // visually linked to other content-ful elements (text, images, etc.).
	  this._markDataTables(articleContent);
  
	  this._fixLazyImages(articleContent);
  
	  // Clean out junk from the article content
	  this._cleanConditionally(articleContent, "form");
	  this._cleanConditionally(articleContent, "fieldset");
	  this._clean(articleContent, "object");
	  this._clean(articleContent, "embed");
	  this._clean(articleContent, "footer");
	  this._clean(articleContent, "link");
	  this._clean(articleContent, "aside");
  
	  // Clean out elements with little content that have "share" in their id/class combinations from final top candidates,
	  // which means we don't remove the top candidates even they have "share".
  
	  var shareElementThreshold = this.DEFAULT_CHAR_THRESHOLD;
  
	  this._forEachNode(articleContent.children, function (topCandidate) {
		this._cleanMatchedNodes(topCandidate, function (node, matchString) {
		  return this.REGEXPS.shareElements.test(matchString) && node.textContent.length < shareElementThreshold;
		});
	  });
  
	  this._clean(articleContent, "iframe");
	  this._clean(articleContent, "input");
	  this._clean(articleContent, "textarea");
	  this._clean(articleContent, "select");
	  this._clean(articleContent, "button");
	  this._cleanHeaders(articleContent);
  
	  // Do these last as the previous stuff may have removed junk
	  // that will affect these
	  this._cleanConditionally(articleContent, "table");
	  this._cleanConditionally(articleContent, "ul");
	  this._cleanConditionally(articleContent, "div");
  
	  // replace H1 with H2 as H1 should be only title that is displayed separately
	  this._replaceNodeTags(this._getAllNodesWithTag(articleContent, ["h1"]), "h2");
  
	  // Remove extra paragraphs
	  this._removeNodes(this._getAllNodesWithTag(articleContent, ["p"]), function (paragraph) {
		var imgCount = paragraph.getElementsByTagName("img").length;
		var embedCount = paragraph.getElementsByTagName("embed").length;
		var objectCount = paragraph.getElementsByTagName("object").length;
		// At this point, nasty iframes have been removed, only remain embedded video ones.
		var iframeCount = paragraph.getElementsByTagName("iframe").length;
		var totalCount = imgCount + embedCount + objectCount + iframeCount;
  
		return totalCount === 0 && !this._getInnerText(paragraph, false);
	  });
  
	  this._forEachNode(this._getAllNodesWithTag(articleContent, ["br"]), function(br) {
		var next = this._nextNode(br.nextSibling);
		if (next && next.tagName == "P")
		  br.parentNode.removeChild(br);
	  });
  
	  // Remove single-cell tables
	  this._forEachNode(this._getAllNodesWithTag(articleContent, ["table"]), function(table) {
		var tbody = this._hasSingleTagInsideElement(table, "TBODY") ? table.firstElementChild : table;
		if (this._hasSingleTagInsideElement(tbody, "TR")) {
		  var row = tbody.firstElementChild;
		  if (this._hasSingleTagInsideElement(row, "TD")) {
			var cell = row.firstElementChild;
			cell = this._setNodeTag(cell, this._everyNode(cell.childNodes, this._isPhrasingContent) ? "P" : "DIV");
			table.parentNode.replaceChild(cell, table);
		  }
		}
	  });
	},
  
	/**
	 * Initialize a node with the readability object. Also checks the
	 * className/id for special names to add to its score.
	 *
	 * @param Element
	 * @return void
	**/
	_initializeNode: function(node) {
	  node.readability = {"contentScore": 0};
  
	  switch (node.tagName) {
		case "DIV":
		  node.readability.contentScore += 5;
		  break;
  
		case "PRE":
		case "TD":
		case "BLOCKQUOTE":
		  node.readability.contentScore += 3;
		  break;
  
		case "ADDRESS":
		case "OL":
		case "UL":
		case "DL":
		case "DD":
		case "DT":
		case "LI":
		case "FORM":
		  node.readability.contentScore -= 3;
		  break;
  
		case "H1":
		case "H2":
		case "H3":
		case "H4":
		case "H5":
		case "H6":
		case "TH":
		  node.readability.contentScore -= 5;
		  break;
	  }
  
	  node.readability.contentScore += this._getClassWeight(node);
	},
  
	_removeAndGetNext: function(node) {
	  var nextNode = this._getNextNode(node, true);
	  node.parentNode.removeChild(node);
	  return nextNode;
	},
  
	/**
	 * Traverse the DOM from node to node, starting at the node passed in.
	 * Pass true for the second parameter to indicate this node itself
	 * (and its kids) are going away, and we want the next node over.
	 *
	 * Calling this in a loop will traverse the DOM depth-first.
	 */
	_getNextNode: function(node, ignoreSelfAndKids) {
	  // First check for kids if those aren't being ignored
	  if (!ignoreSelfAndKids && node.firstElementChild) {
		return node.firstElementChild;
	  }
	  // Then for siblings...
	  if (node.nextElementSibling) {
		return node.nextElementSibling;
	  }
	  // And finally, move up the parent chain *and* find a sibling
	  // (because this is depth-first traversal, we will have already
	  // seen the parent nodes themselves).
	  do {
		node = node.parentNode;
	  } while (node && !node.nextElementSibling);
	  return node && node.nextElementSibling;
	},
  
	// compares second text to first one
	// 1 = same text, 0 = completely different text
	// works the way that it splits both texts into words and then finds words that are unique in second text
	// the result is given by the lower length of unique parts
	_textSimilarity: function(textA, textB) {
	  var tokensA = textA.toLowerCase().split(this.REGEXPS.tokenize).filter(Boolean);
	  var tokensB = textB.toLowerCase().split(this.REGEXPS.tokenize).filter(Boolean);
	  if (!tokensA.length || !tokensB.length) {
		return 0;
	  }
	  var uniqTokensB = tokensB.filter(token => !tokensA.includes(token));
	  var distanceB = uniqTokensB.join(" ").length / tokensB.join(" ").length;
	  return 1 - distanceB;
	},
  
	_checkByline: function(node, matchString) {
	  if (this._articleByline) {
		return false;
	  }
  
	  if (node.getAttribute !== undefined) {
		var rel = node.getAttribute("rel");
		var itemprop = node.getAttribute("itemprop");
	  }
  
	  if ((rel === "author" || (itemprop && itemprop.indexOf("author") !== -1) || this.REGEXPS.byline.test(matchString)) && this._isValidByline(node.textContent)) {
		this._articleByline = node.textContent.trim();
		return true;
	  }
  
	  return false;
	},
  
	_getNodeAncestors: function(node, maxDepth) {
	  maxDepth = maxDepth || 0;
	  var i = 0, ancestors = [];
	  while (node.parentNode) {
		ancestors.push(node.parentNode);
		if (maxDepth && ++i === maxDepth)
		  break;
		node = node.parentNode;
	  }
	  return ancestors;
	},
  
	/***
	 * grabArticle - Using a variety of metrics (content score, classname, element types), find the content that is
	 *         most likely to be the stuff a user wants to read. Then return it wrapped up in a div.
	 *
	 * @param page a document to run upon. Needs to be a full document, complete with body.
	 * @return Element
	**/
	_grabArticle: function (page) {
	  this.log("**** grabArticle ****");
	  var doc = this._doc;
	  var isPaging = page !== null;
	  page = page ? page : this._doc.body;
  
	  // We can't grab an article if we don't have a page!
	  if (!page) {
		this.log("No body found in document. Abort.");
		return null;
	  }
  
	  var pageCacheHtml = page.innerHTML;
  
	  while (true) {
		this.log("Starting grabArticle loop");
		var stripUnlikelyCandidates = this._flagIsActive(this.FLAG_STRIP_UNLIKELYS);
  
		// First, node prepping. Trash nodes that look cruddy (like ones with the
		// class name "comment", etc), and turn divs into P tags where they have been
		// used inappropriately (as in, where they contain no other block level elements.)
		var elementsToScore = [];
		var node = this._doc.documentElement;
  
		let shouldRemoveTitleHeader = true;
  
		while (node) {
  
		  if (node.tagName === "HTML") {
			this._articleLang = node.getAttribute("lang");
		  }
  
		  var matchString = node.className + " " + node.id;
  
		  if (!this._isProbablyVisible(node)) {
			this.log("Removing hidden node - " + matchString);
			node = this._removeAndGetNext(node);
			continue;
		  }
  
		  // User is not able to see elements applied with both "aria-modal = true" and "role = dialog"
		  if (node.getAttribute("aria-modal") == "true" && node.getAttribute("role") == "dialog") {
			node = this._removeAndGetNext(node);
			continue;
		  }
  
		  // Check to see if this node is a byline, and remove it if it is.
		  if (this._checkByline(node, matchString)) {
			node = this._removeAndGetNext(node);
			continue;
		  }
  
		  if (shouldRemoveTitleHeader && this._headerDuplicatesTitle(node)) {
			this.log("Removing header: ", node.textContent.trim(), this._articleTitle.trim());
			shouldRemoveTitleHeader = false;
			node = this._removeAndGetNext(node);
			continue;
		  }
  
		  // Remove unlikely candidates
		  if (stripUnlikelyCandidates) {
			if (this.REGEXPS.unlikelyCandidates.test(matchString) &&
				!this.REGEXPS.okMaybeItsACandidate.test(matchString) &&
				!this._hasAncestorTag(node, "table") &&
				!this._hasAncestorTag(node, "code") &&
				node.tagName !== "BODY" &&
				node.tagName !== "A") {
			  this.log("Removing unlikely candidate - " + matchString);
			  node = this._removeAndGetNext(node);
			  continue;
			}
  
			if (this.UNLIKELY_ROLES.includes(node.getAttribute("role"))) {
			  this.log("Removing content with role " + node.getAttribute("role") + " - " + matchString);
			  node = this._removeAndGetNext(node);
			  continue;
			}
		  }
  
		  // Remove DIV, SECTION, and HEADER nodes without any content(e.g. text, image, video, or iframe).
		  if ((node.tagName === "DIV" || node.tagName === "SECTION" || node.tagName === "HEADER" ||
			   node.tagName === "H1" || node.tagName === "H2" || node.tagName === "H3" ||
			   node.tagName === "H4" || node.tagName === "H5" || node.tagName === "H6") &&
			  this._isElementWithoutContent(node)) {
			node = this._removeAndGetNext(node);
			continue;
		  }
  
		  if (this.DEFAULT_TAGS_TO_SCORE.indexOf(node.tagName) !== -1) {
			elementsToScore.push(node);
		  }
  
		  // Turn all divs that don't have children block level elements into p's
		  if (node.tagName === "DIV") {
			// Put phrasing content into paragraphs.
			var p = null;
			var childNode = node.firstChild;
			while (childNode) {
			  var nextSibling = childNode.nextSibling;
			  if (this._isPhrasingContent(childNode)) {
				if (p !== null) {
				  p.appendChild(childNode);
				} else if (!this._isWhitespace(childNode)) {
				  p = doc.createElement("p");
				  node.replaceChild(p, childNode);
				  p.appendChild(childNode);
				}
			  } else if (p !== null) {
				while (p.lastChild && this._isWhitespace(p.lastChild)) {
				  p.removeChild(p.lastChild);
				}
				p = null;
			  }
			  childNode = nextSibling;
			}
  
			// Sites like http://mobile.slate.com encloses each paragraph with a DIV
			// element. DIVs with only a P element inside and no text content can be
			// safely converted into plain P elements to avoid confusing the scoring
			// algorithm with DIVs with are, in practice, paragraphs.
			if (this._hasSingleTagInsideElement(node, "P") && this._getLinkDensity(node) < 0.25) {
			  var newNode = node.children[0];
			  node.parentNode.replaceChild(newNode, node);
			  node = newNode;
			  elementsToScore.push(node);
			} else if (!this._hasChildBlockElement(node)) {
			  node = this._setNodeTag(node, "P");
			  elementsToScore.push(node);
			}
		  }
		  node = this._getNextNode(node);
		}
  
		/**
		 * Loop through all paragraphs, and assign a score to them based on how content-y they look.
		 * Then add their score to their parent node.
		 *
		 * A score is determined by things like number of commas, class names, etc. Maybe eventually link density.
		**/
		var candidates = [];
		this._forEachNode(elementsToScore, function(elementToScore) {
		  if (!elementToScore.parentNode || typeof(elementToScore.parentNode.tagName) === "undefined")
			return;
  
		  // If this paragraph is less than 25 characters, don't even count it.
		  var innerText = this._getInnerText(elementToScore);
		  if (innerText.length < 25)
			return;
  
		  // Exclude nodes with no ancestor.
		  var ancestors = this._getNodeAncestors(elementToScore, 5);
		  if (ancestors.length === 0)
			return;
  
		  var contentScore = 0;
  
		  // Add a point for the paragraph itself as a base.
		  contentScore += 1;
  
		  // Add points for any commas within this paragraph.
		  contentScore += innerText.split(this.REGEXPS.commas).length;
  
		  // For every 100 characters in this paragraph, add another point. Up to 3 points.
		  contentScore += Math.min(Math.floor(innerText.length / 100), 3);
  
		  // Initialize and score ancestors.
		  this._forEachNode(ancestors, function(ancestor, level) {
			if (!ancestor.tagName || !ancestor.parentNode || typeof(ancestor.parentNode.tagName) === "undefined")
			  return;
  
			if (typeof(ancestor.readability) === "undefined") {
			  this._initializeNode(ancestor);
			  candidates.push(ancestor);
			}
  
			// Node score divider:
			// - parent:             1 (no division)
			// - grandparent:        2
			// - great grandparent+: ancestor level * 3
			if (level === 0)
			  var scoreDivider = 1;
			else if (level === 1)
			  scoreDivider = 2;
			else
			  scoreDivider = level * 3;
			ancestor.readability.contentScore += contentScore / scoreDivider;
		  });
		});
  
		// After we've calculated scores, loop through all of the possible
		// candidate nodes we found and find the one with the highest score.
		var topCandidates = [];
		for (var c = 0, cl = candidates.length; c < cl; c += 1) {
		  var candidate = candidates[c];
  
		  // Scale the final candidates score based on link density. Good content
		  // should have a relatively small link density (5% or less) and be mostly
		  // unaffected by this operation.
		  var candidateScore = candidate.readability.contentScore * (1 - this._getLinkDensity(candidate));
		  candidate.readability.contentScore = candidateScore;
  
		  this.log("Candidate:", candidate, "with score " + candidateScore);
  
		  for (var t = 0; t < this._nbTopCandidates; t++) {
			var aTopCandidate = topCandidates[t];
  
			if (!aTopCandidate || candidateScore > aTopCandidate.readability.contentScore) {
			  topCandidates.splice(t, 0, candidate);
			  if (topCandidates.length > this._nbTopCandidates)
				topCandidates.pop();
			  break;
			}
		  }
		}
  
		var topCandidate = topCandidates[0] || null;
		var neededToCreateTopCandidate = false;
		var parentOfTopCandidate;
  
		// If we still have no top candidate, just use the body as a last resort.
		// We also have to copy the body node so it is something we can modify.
		if (topCandidate === null || topCandidate.tagName === "BODY") {
		  // Move all of the page's children into topCandidate
		  topCandidate = doc.createElement("DIV");
		  neededToCreateTopCandidate = true;
		  // Move everything (not just elements, also text nodes etc.) into the container
		  // so we even include text directly in the body:
		  while (page.firstChild) {
			this.log("Moving child out:", page.firstChild);
			topCandidate.appendChild(page.firstChild);
		  }
  
		  page.appendChild(topCandidate);
  
		  this._initializeNode(topCandidate);
		} else if (topCandidate) {
		  // Find a better top candidate node if it contains (at least three) nodes which belong to `topCandidates` array
		  // and whose scores are quite closed with current `topCandidate` node.
		  var alternativeCandidateAncestors = [];
		  for (var i = 1; i < topCandidates.length; i++) {
			if (topCandidates[i].readability.contentScore / topCandidate.readability.contentScore >= 0.75) {
			  alternativeCandidateAncestors.push(this._getNodeAncestors(topCandidates[i]));
			}
		  }
		  var MINIMUM_TOPCANDIDATES = 3;
		  if (alternativeCandidateAncestors.length >= MINIMUM_TOPCANDIDATES) {
			parentOfTopCandidate = topCandidate.parentNode;
			while (parentOfTopCandidate.tagName !== "BODY") {
			  var listsContainingThisAncestor = 0;
			  for (var ancestorIndex = 0; ancestorIndex < alternativeCandidateAncestors.length && listsContainingThisAncestor < MINIMUM_TOPCANDIDATES; ancestorIndex++) {
				listsContainingThisAncestor += Number(alternativeCandidateAncestors[ancestorIndex].includes(parentOfTopCandidate));
			  }
			  if (listsContainingThisAncestor >= MINIMUM_TOPCANDIDATES) {
				topCandidate = parentOfTopCandidate;
				break;
			  }
			  parentOfTopCandidate = parentOfTopCandidate.parentNode;
			}
		  }
		  if (!topCandidate.readability) {
			this._initializeNode(topCandidate);
		  }
  
		  // Because of our bonus system, parents of candidates might have scores
		  // themselves. They get half of the node. There won't be nodes with higher
		  // scores than our topCandidate, but if we see the score going *up* in the first
		  // few steps up the tree, that's a decent sign that there might be more content
		  // lurking in other places that we want to unify in. The sibling stuff
		  // below does some of that - but only if we've looked high enough up the DOM
		  // tree.
		  parentOfTopCandidate = topCandidate.parentNode;
		  var lastScore = topCandidate.readability.contentScore;
		  // The scores shouldn't get too low.
		  var scoreThreshold = lastScore / 3;
		  while (parentOfTopCandidate.tagName !== "BODY") {
			if (!parentOfTopCandidate.readability) {
			  parentOfTopCandidate = parentOfTopCandidate.parentNode;
			  continue;
			}
			var parentScore = parentOfTopCandidate.readability.contentScore;
			if (parentScore < scoreThreshold)
			  break;
			if (parentScore > lastScore) {
			  // Alright! We found a better parent to use.
			  topCandidate = parentOfTopCandidate;
			  break;
			}
			lastScore = parentOfTopCandidate.readability.contentScore;
			parentOfTopCandidate = parentOfTopCandidate.parentNode;
		  }
  
		  // If the top candidate is the only child, use parent instead. This will help sibling
		  // joining logic when adjacent content is actually located in parent's sibling node.
		  parentOfTopCandidate = topCandidate.parentNode;
		  while (parentOfTopCandidate.tagName != "BODY" && parentOfTopCandidate.children.length == 1) {
			topCandidate = parentOfTopCandidate;
			parentOfTopCandidate = topCandidate.parentNode;
		  }
		  if (!topCandidate.readability) {
			this._initializeNode(topCandidate);
		  }
		}
  
		// Now that we have the top candidate, look through its siblings for content
		// that might also be related. Things like preambles, content split by ads
		// that we removed, etc.
		var articleContent = doc.createElement("DIV");
		if (isPaging)
		  articleContent.id = "readability-content";
  
		var siblingScoreThreshold = Math.max(10, topCandidate.readability.contentScore * 0.2);
		// Keep potential top candidate's parent node to try to get text direction of it later.
		parentOfTopCandidate = topCandidate.parentNode;
		var siblings = parentOfTopCandidate.children;
  
		for (var s = 0, sl = siblings.length; s < sl; s++) {
		  var sibling = siblings[s];
		  var append = false;
  
		  this.log("Looking at sibling node:", sibling, sibling.readability ? ("with score " + sibling.readability.contentScore) : "");
		  this.log("Sibling has score", sibling.readability ? sibling.readability.contentScore : "Unknown");
  
		  if (sibling === topCandidate) {
			append = true;
		  } else {
			var contentBonus = 0;
  
			// Give a bonus if sibling nodes and top candidates have the example same classname
			if (sibling.className === topCandidate.className && topCandidate.className !== "")
			  contentBonus += topCandidate.readability.contentScore * 0.2;
  
			if (sibling.readability &&
				((sibling.readability.contentScore + contentBonus) >= siblingScoreThreshold)) {
			  append = true;
			} else if (sibling.nodeName === "P") {
			  var linkDensity = this._getLinkDensity(sibling);
			  var nodeContent = this._getInnerText(sibling);
			  var nodeLength = nodeContent.length;
  
			  if (nodeLength > 80 && linkDensity < 0.25) {
				append = true;
			  } else if (nodeLength < 80 && nodeLength > 0 && linkDensity === 0 &&
						 nodeContent.search(/\.( |$)/) !== -1) {
				append = true;
			  }
			}
		  }
  
		  if (append) {
			this.log("Appending node:", sibling);
  
			if (this.ALTER_TO_DIV_EXCEPTIONS.indexOf(sibling.nodeName) === -1) {
			  // We have a node that isn't a common block level element, like a form or td tag.
			  // Turn it into a div so it doesn't get filtered out later by accident.
			  this.log("Altering sibling:", sibling, "to div.");
  
			  sibling = this._setNodeTag(sibling, "DIV");
			}
  
			articleContent.appendChild(sibling);
			// Fetch children again to make it compatible
			// with DOM parsers without live collection support.
			siblings = parentOfTopCandidate.children;
			// siblings is a reference to the children array, and
			// sibling is removed from the array when we call appendChild().
			// As a result, we must revisit this index since the nodes
			// have been shifted.
			s -= 1;
			sl -= 1;
		  }
		}
  
		if (this._debug)
		  this.log("Article content pre-prep: " + articleContent.innerHTML);
		// So we have all of the content that we need. Now we clean it up for presentation.
		this._prepArticle(articleContent);
		if (this._debug)
		  this.log("Article content post-prep: " + articleContent.innerHTML);
  
		if (neededToCreateTopCandidate) {
		  // We already created a fake div thing, and there wouldn't have been any siblings left
		  // for the previous loop, so there's no point trying to create a new div, and then
		  // move all the children over. Just assign IDs and class names here. No need to append
		  // because that already happened anyway.
		  topCandidate.id = "readability-page-1";
		  topCandidate.className = "page";
		} else {
		  var div = doc.createElement("DIV");
		  div.id = "readability-page-1";
		  div.className = "page";
		  while (articleContent.firstChild) {
			div.appendChild(articleContent.firstChild);
		  }
		  articleContent.appendChild(div);
		}
  
		if (this._debug)
		  this.log("Article content after paging: " + articleContent.innerHTML);
  
		var parseSuccessful = true;
  
		// Now that we've gone through the full algorithm, check to see if
		// we got any meaningful content. If we didn't, we may need to re-run
		// grabArticle with different flags set. This gives us a higher likelihood of
		// finding the content, and the sieve approach gives us a higher likelihood of
		// finding the -right- content.
		var textLength = this._getInnerText(articleContent, true).length;
		if (textLength < this._charThreshold) {
		  parseSuccessful = false;
		  page.innerHTML = pageCacheHtml;
  
		  if (this._flagIsActive(this.FLAG_STRIP_UNLIKELYS)) {
			this._removeFlag(this.FLAG_STRIP_UNLIKELYS);
			this._attempts.push({articleContent: articleContent, textLength: textLength});
		  } else if (this._flagIsActive(this.FLAG_WEIGHT_CLASSES)) {
			this._removeFlag(this.FLAG_WEIGHT_CLASSES);
			this._attempts.push({articleContent: articleContent, textLength: textLength});
		  } else if (this._flagIsActive(this.FLAG_CLEAN_CONDITIONALLY)) {
			this._removeFlag(this.FLAG_CLEAN_CONDITIONALLY);
			this._attempts.push({articleContent: articleContent, textLength: textLength});
		  } else {
			this._attempts.push({articleContent: articleContent, textLength: textLength});
			// No luck after removing flags, just return the longest text we found during the different loops
			this._attempts.sort(function (a, b) {
			  return b.textLength - a.textLength;
			});
  
			// But first check if we actually have something
			if (!this._attempts[0].textLength) {
			  return null;
			}
  
			articleContent = this._attempts[0].articleContent;
			parseSuccessful = true;
		  }
		}
  
		if (parseSuccessful) {
		  // Find out text direction from ancestors of final top candidate.
		  var ancestors = [parentOfTopCandidate, topCandidate].concat(this._getNodeAncestors(parentOfTopCandidate));
		  this._someNode(ancestors, function(ancestor) {
			if (!ancestor.tagName)
			  return false;
			var articleDir = ancestor.getAttribute("dir");
			if (articleDir) {
			  this._articleDir = articleDir;
			  return true;
			}
			return false;
		  });
		  return articleContent;
		}
	  }
	},
  
	/**
	 * Check whether the input string could be a byline.
	 * This verifies that the input is a string, and that the length
	 * is less than 100 chars.
	 *
	 * @param possibleByline {string} - a string to check whether its a byline.
	 * @return Boolean - whether the input string is a byline.
	 */
	_isValidByline: function(byline) {
	  if (typeof byline == "string" || byline instanceof String) {
		byline = byline.trim();
		return (byline.length > 0) && (byline.length < 100);
	  }
	  return false;
	},
  
	/**
	 * Converts some of the common HTML entities in string to their corresponding characters.
	 *
	 * @param str {string} - a string to unescape.
	 * @return string without HTML entity.
	 */
	_unescapeHtmlEntities: function(str) {
	  if (!str) {
		return str;
	  }
  
	  var htmlEscapeMap = this.HTML_ESCAPE_MAP;
	  return str.replace(/&(quot|amp|apos|lt|gt);/g, function(_, tag) {
		return htmlEscapeMap[tag];
	  }).replace(/&#(?:x([0-9a-z]{1,4})|([0-9]{1,4}));/gi, function(_, hex, numStr) {
		var num = parseInt(hex || numStr, hex ? 16 : 10);
		return String.fromCharCode(num);
	  });
	},
  
	/**
	 * Try to extract metadata from JSON-LD object.
	 * For now, only Schema.org objects of type Article or its subtypes are supported.
	 * @return Object with any metadata that could be extracted (possibly none)
	 */
	_getJSONLD: function (doc) {
	  var scripts = this._getAllNodesWithTag(doc, ["script"]);
  
	  var metadata;
  
	  this._forEachNode(scripts, function(jsonLdElement) {
		if (!metadata && jsonLdElement.getAttribute("type") === "application/ld+json") {
		  try {
			// Strip CDATA markers if present
			var content = jsonLdElement.textContent.replace(/^\s*<!\[CDATA\[|\]\]>\s*$/g, "");
			var parsed = JSON.parse(content);
			if (
			  !parsed["@context"] ||
			  !parsed["@context"].match(/^https?\:\/\/schema\.org$/)
			) {
			  return;
			}
  
			if (!parsed["@type"] && Array.isArray(parsed["@graph"])) {
			  parsed = parsed["@graph"].find(function(it) {
				return (it["@type"] || "").match(
				  this.REGEXPS.jsonLdArticleTypes
				);
			  });
			}
  
			if (
			  !parsed ||
			  !parsed["@type"] ||
			  !parsed["@type"].match(this.REGEXPS.jsonLdArticleTypes)
			) {
			  return;
			}
  
			metadata = {};
  
			if (typeof parsed.name === "string" && typeof parsed.headline === "string" && parsed.name !== parsed.headline) {
			  // we have both name and headline element in the JSON-LD. They should both be the same but some websites like aktualne.cz
			  // put their own name into "name" and the article title to "headline" which confuses Readability. So we try to check if either
			  // "name" or "headline" closely matches the html title, and if so, use that one. If not, then we use "name" by default.
  
			  var title = this._getArticleTitle();
			  var nameMatches = this._textSimilarity(parsed.name, title) > 0.75;
			  var headlineMatches = this._textSimilarity(parsed.headline, title) > 0.75;
  
			  if (headlineMatches && !nameMatches) {
				metadata.title = parsed.headline;
			  } else {
				metadata.title = parsed.name;
			  }
			} else if (typeof parsed.name === "string") {
			  metadata.title = parsed.name.trim();
			} else if (typeof parsed.headline === "string") {
			  metadata.title = parsed.headline.trim();
			}
			if (parsed.author) {
			  if (typeof parsed.author.name === "string") {
				metadata.byline = parsed.author.name.trim();
			  } else if (Array.isArray(parsed.author) && parsed.author[0] && typeof parsed.author[0].name === "string") {
				metadata.byline = parsed.author
				  .filter(function(author) {
					return author && typeof author.name === "string";
				  })
				  .map(function(author) {
					return author.name.trim();
				  })
				  .join(", ");
			  }
			}
			if (typeof parsed.description === "string") {
			  metadata.excerpt = parsed.description.trim();
			}
			if (
			  parsed.publisher &&
			  typeof parsed.publisher.name === "string"
			) {
			  metadata.siteName = parsed.publisher.name.trim();
			}
			return;
		  } catch (err) {
			this.log(err.message);
		  }
		}
	  });
	  return metadata ? metadata : {};
	},
  
	/**
	 * Attempts to get excerpt and byline metadata for the article.
	 *
	 * @param {Object} jsonld — object containing any metadata that
	 * could be extracted from JSON-LD object.
	 *
	 * @return Object with optional "excerpt" and "byline" properties
	 */
	_getArticleMetadata: function(jsonld) {
	  var metadata = {};
	  var values = {};
	  var metaElements = this._doc.getElementsByTagName("meta");
  
	  // property is a space-separated list of values
	  var propertyPattern = /\s*(dc|dcterm|og|twitter)\s*:\s*(author|creator|description|title|site_name)\s*/gi;
  
	  // name is a single value
	  var namePattern = /^\s*(?:(dc|dcterm|og|twitter|weibo:(article|webpage))\s*[\.:]\s*)?(author|creator|description|title|site_name)\s*$/i;
  
	  // Find description tags.
	  this._forEachNode(metaElements, function(element) {
		var elementName = element.getAttribute("name");
		var elementProperty = element.getAttribute("property");
		var content = element.getAttribute("content");
		if (!content) {
		  return;
		}
		var matches = null;
		var name = null;
  
		if (elementProperty) {
		  matches = elementProperty.match(propertyPattern);
		  if (matches) {
			// Convert to lowercase, and remove any whitespace
			// so we can match below.
			name = matches[0].toLowerCase().replace(/\s/g, "");
			// multiple authors
			values[name] = content.trim();
		  }
		}
		if (!matches && elementName && namePattern.test(elementName)) {
		  name = elementName;
		  if (content) {
			// Convert to lowercase, remove any whitespace, and convert dots
			// to colons so we can match below.
			name = name.toLowerCase().replace(/\s/g, "").replace(/\./g, ":");
			values[name] = content.trim();
		  }
		}
	  });
  
	  // get title
	  metadata.title = jsonld.title ||
					   values["dc:title"] ||
					   values["dcterm:title"] ||
					   values["og:title"] ||
					   values["weibo:article:title"] ||
					   values["weibo:webpage:title"] ||
					   values["title"] ||
					   values["twitter:title"];
  
	  if (!metadata.title) {
		metadata.title = this._getArticleTitle();
	  }
  
	  // get author
	  metadata.byline = jsonld.byline ||
						values["dc:creator"] ||
						values["dcterm:creator"] ||
						values["author"];
  
	  // get description
	  metadata.excerpt = jsonld.excerpt ||
						 values["dc:description"] ||
						 values["dcterm:description"] ||
						 values["og:description"] ||
						 values["weibo:article:description"] ||
						 values["weibo:webpage:description"] ||
						 values["description"] ||
						 values["twitter:description"];
  
	  // get site name
	  metadata.siteName = jsonld.siteName ||
						  values["og:site_name"];
  
	  // in many sites the meta value is escaped with HTML entities,
	  // so here we need to unescape it
	  metadata.title = this._unescapeHtmlEntities(metadata.title);
	  metadata.byline = this._unescapeHtmlEntities(metadata.byline);
	  metadata.excerpt = this._unescapeHtmlEntities(metadata.excerpt);
	  metadata.siteName = this._unescapeHtmlEntities(metadata.siteName);
  
	  return metadata;
	},
  
	/**
	 * Check if node is image, or if node contains exactly only one image
	 * whether as a direct child or as its descendants.
	 *
	 * @param Element
	**/
	_isSingleImage: function(node) {
	  if (node.tagName === "IMG") {
		return true;
	  }
  
	  if (node.children.length !== 1 || node.textContent.trim() !== "") {
		return false;
	  }
  
	  return this._isSingleImage(node.children[0]);
	},
  
	/**
	 * Find all <noscript> that are located after <img> nodes, and which contain only one
	 * <img> element. Replace the first image with the image from inside the <noscript> tag,
	 * and remove the <noscript> tag. This improves the quality of the images we use on
	 * some sites (e.g. Medium).
	 *
	 * @param Element
	**/
	_unwrapNoscriptImages: function(doc) {
	  // Find img without source or attributes that might contains image, and remove it.
	  // This is done to prevent a placeholder img is replaced by img from noscript in next step.
	  var imgs = Array.from(doc.getElementsByTagName("img"));
	  this._forEachNode(imgs, function(img) {
		for (var i = 0; i < img.attributes.length; i++) {
		  var attr = img.attributes[i];
		  switch (attr.name) {
			case "src":
			case "srcset":
			case "data-src":
			case "data-srcset":
			  return;
		  }
  
		  if (/\.(jpg|jpeg|png|webp)/i.test(attr.value)) {
			return;
		  }
		}
  
		img.parentNode.removeChild(img);
	  });
  
	  // Next find noscript and try to extract its image
	  var noscripts = Array.from(doc.getElementsByTagName("noscript"));
	  this._forEachNode(noscripts, function(noscript) {
		// Parse content of noscript and make sure it only contains image
		var tmp = doc.createElement("div");
		tmp.innerHTML = noscript.innerHTML;
		if (!this._isSingleImage(tmp)) {
		  return;
		}
  
		// If noscript has previous sibling and it only contains image,
		// replace it with noscript content. However we also keep old
		// attributes that might contains image.
		var prevElement = noscript.previousElementSibling;
		if (prevElement && this._isSingleImage(prevElement)) {
		  var prevImg = prevElement;
		  if (prevImg.tagName !== "IMG") {
			prevImg = prevElement.getElementsByTagName("img")[0];
		  }
  
		  var newImg = tmp.getElementsByTagName("img")[0];
		  for (var i = 0; i < prevImg.attributes.length; i++) {
			var attr = prevImg.attributes[i];
			if (attr.value === "") {
			  continue;
			}
  
			if (attr.name === "src" || attr.name === "srcset" || /\.(jpg|jpeg|png|webp)/i.test(attr.value)) {
			  if (newImg.getAttribute(attr.name) === attr.value) {
				continue;
			  }
  
			  var attrName = attr.name;
			  if (newImg.hasAttribute(attrName)) {
				attrName = "data-old-" + attrName;
			  }
  
			  newImg.setAttribute(attrName, attr.value);
			}
		  }
  
		  noscript.parentNode.replaceChild(tmp.firstElementChild, prevElement);
		}
	  });
	},
  
	/**
	 * Removes script tags from the document.
	 *
	 * @param Element
	**/
	_removeScripts: function(doc) {
	  this._removeNodes(this._getAllNodesWithTag(doc, ["script", "noscript"]));
	},
  
	/**
	 * Check if this node has only whitespace and a single element with given tag
	 * Returns false if the DIV node contains non-empty text nodes
	 * or if it contains no element with given tag or more than 1 element.
	 *
	 * @param Element
	 * @param string tag of child element
	**/
	_hasSingleTagInsideElement: function(element, tag) {
	  // There should be exactly 1 element child with given tag
	  if (element.children.length != 1 || element.children[0].tagName !== tag) {
		return false;
	  }
  
	  // And there should be no text nodes with real content
	  return !this._someNode(element.childNodes, function(node) {
		return node.nodeType === this.TEXT_NODE &&
			   this.REGEXPS.hasContent.test(node.textContent);
	  });
	},
  
	_isElementWithoutContent: function(node) {
	  return node.nodeType === this.ELEMENT_NODE &&
		node.textContent.trim().length == 0 &&
		(node.children.length == 0 ||
		 node.children.length == node.getElementsByTagName("br").length + node.getElementsByTagName("hr").length);
	},
  
	/**
	 * Determine whether element has any children block level elements.
	 *
	 * @param Element
	 */
	_hasChildBlockElement: function (element) {
	  return this._someNode(element.childNodes, function(node) {
		return this.DIV_TO_P_ELEMS.has(node.tagName) ||
			   this._hasChildBlockElement(node);
	  });
	},
  
	/***
	 * Determine if a node qualifies as phrasing content.
	 * https://developer.mozilla.org/en-US/docs/Web/Guide/HTML/Content_categories#Phrasing_content
	**/
	_isPhrasingContent: function(node) {
	  return node.nodeType === this.TEXT_NODE || this.PHRASING_ELEMS.indexOf(node.tagName) !== -1 ||
		((node.tagName === "A" || node.tagName === "DEL" || node.tagName === "INS") &&
		  this._everyNode(node.childNodes, this._isPhrasingContent));
	},
  
	_isWhitespace: function(node) {
	  return (node.nodeType === this.TEXT_NODE && node.textContent.trim().length === 0) ||
			 (node.nodeType === this.ELEMENT_NODE && node.tagName === "BR");
	},
  
	/**
	 * Get the inner text of a node - cross browser compatibly.
	 * This also strips out any excess whitespace to be found.
	 *
	 * @param Element
	 * @param Boolean normalizeSpaces (default: true)
	 * @return string
	**/
	_getInnerText: function(e, normalizeSpaces) {
	  normalizeSpaces = (typeof normalizeSpaces === "undefined") ? true : normalizeSpaces;
	  var textContent = e.textContent.trim();
  
	  if (normalizeSpaces) {
		return textContent.replace(this.REGEXPS.normalize, " ");
	  }
	  return textContent;
	},
  
	/**
	 * Get the number of times a string s appears in the node e.
	 *
	 * @param Element
	 * @param string - what to split on. Default is ","
	 * @return number (integer)
	**/
	_getCharCount: function(e, s) {
	  s = s || ",";
	  return this._getInnerText(e).split(s).length - 1;
	},
  
	/**
	 * Remove the style attribute on every e and under.
	 * TODO: Test if getElementsByTagName(*) is faster.
	 *
	 * @param Element
	 * @return void
	**/
	_cleanStyles: function(e) {
	  if (!e || e.tagName.toLowerCase() === "svg")
		return;
  
	  // Remove `style` and deprecated presentational attributes
	  for (var i = 0; i < this.PRESENTATIONAL_ATTRIBUTES.length; i++) {
		e.removeAttribute(this.PRESENTATIONAL_ATTRIBUTES[i]);
	  }
  
	  if (this.DEPRECATED_SIZE_ATTRIBUTE_ELEMS.indexOf(e.tagName) !== -1) {
		e.removeAttribute("width");
		e.removeAttribute("height");
	  }
  
	  var cur = e.firstElementChild;
	  while (cur !== null) {
		this._cleanStyles(cur);
		cur = cur.nextElementSibling;
	  }
	},
  
	/**
	 * Get the density of links as a percentage of the content
	 * This is the amount of text that is inside a link divided by the total text in the node.
	 *
	 * @param Element
	 * @return number (float)
	**/
	_getLinkDensity: function(element) {
	  var textLength = this._getInnerText(element).length;
	  if (textLength === 0)
		return 0;
  
	  var linkLength = 0;
  
	  // XXX implement _reduceNodeList?
	  this._forEachNode(element.getElementsByTagName("a"), function(linkNode) {
		var href = linkNode.getAttribute("href");
		var coefficient = href && this.REGEXPS.hashUrl.test(href) ? 0.3 : 1;
		linkLength += this._getInnerText(linkNode).length * coefficient;
	  });
  
	  return linkLength / textLength;
	},
  
	/**
	 * Get an elements class/id weight. Uses regular expressions to tell if this
	 * element looks good or bad.
	 *
	 * @param Element
	 * @return number (Integer)
	**/
	_getClassWeight: function(e) {
	  if (!this._flagIsActive(this.FLAG_WEIGHT_CLASSES))
		return 0;
  
	  var weight = 0;
  
	  // Look for a special classname
	  if (typeof(e.className) === "string" && e.className !== "") {
		if (this.REGEXPS.negative.test(e.className))
		  weight -= 25;
  
		if (this.REGEXPS.positive.test(e.className))
		  weight += 25;
	  }
  
	  // Look for a special ID
	  if (typeof(e.id) === "string" && e.id !== "") {
		if (this.REGEXPS.negative.test(e.id))
		  weight -= 25;
  
		if (this.REGEXPS.positive.test(e.id))
		  weight += 25;
	  }
  
	  return weight;
	},
  
	/**
	 * Clean a node of all elements of type "tag".
	 * (Unless it's a youtube/vimeo video. People love movies.)
	 *
	 * @param Element
	 * @param string tag to clean
	 * @return void
	 **/
	_clean: function(e, tag) {
	  var isEmbed = ["object", "embed", "iframe"].indexOf(tag) !== -1;
  
	  this._removeNodes(this._getAllNodesWithTag(e, [tag]), function(element) {
		// Allow youtube and vimeo videos through as people usually want to see those.
		if (isEmbed) {
		  // First, check the elements attributes to see if any of them contain youtube or vimeo
		  for (var i = 0; i < element.attributes.length; i++) {
			if (this._allowedVideoRegex.test(element.attributes[i].value)) {
			  return false;
			}
		  }
  
		  // For embed with <object> tag, check inner HTML as well.
		  if (element.tagName === "object" && this._allowedVideoRegex.test(element.innerHTML)) {
			return false;
		  }
		}
  
		return true;
	  });
	},
  
	/**
	 * Check if a given node has one of its ancestor tag name matching the
	 * provided one.
	 * @param  HTMLElement node
	 * @param  String      tagName
	 * @param  Number      maxDepth
	 * @param  Function    filterFn a filter to invoke to determine whether this node 'counts'
	 * @return Boolean
	 */
	_hasAncestorTag: function(node, tagName, maxDepth, filterFn) {
	  maxDepth = maxDepth || 3;
	  tagName = tagName.toUpperCase();
	  var depth = 0;
	  while (node.parentNode) {
		if (maxDepth > 0 && depth > maxDepth)
		  return false;
		if (node.parentNode.tagName === tagName && (!filterFn || filterFn(node.parentNode)))
		  return true;
		node = node.parentNode;
		depth++;
	  }
	  return false;
	},
  
	/**
	 * Return an object indicating how many rows and columns this table has.
	 */
	_getRowAndColumnCount: function(table) {
	  var rows = 0;
	  var columns = 0;
	  var trs = table.getElementsByTagName("tr");
	  for (var i = 0; i < trs.length; i++) {
		var rowspan = trs[i].getAttribute("rowspan") || 0;
		if (rowspan) {
		  rowspan = parseInt(rowspan, 10);
		}
		rows += (rowspan || 1);
  
		// Now look for column-related info
		var columnsInThisRow = 0;
		var cells = trs[i].getElementsByTagName("td");
		for (var j = 0; j < cells.length; j++) {
		  var colspan = cells[j].getAttribute("colspan") || 0;
		  if (colspan) {
			colspan = parseInt(colspan, 10);
		  }
		  columnsInThisRow += (colspan || 1);
		}
		columns = Math.max(columns, columnsInThisRow);
	  }
	  return {rows: rows, columns: columns};
	},
  
	/**
	 * Look for 'data' (as opposed to 'layout') tables, for which we use
	 * similar checks as
	 * https://searchfox.org/mozilla-central/rev/f82d5c549f046cb64ce5602bfd894b7ae807c8f8/accessible/generic/TableAccessible.cpp#19
	 */
	_markDataTables: function(root) {
	  var tables = root.getElementsByTagName("table");
	  for (var i = 0; i < tables.length; i++) {
		var table = tables[i];
		var role = table.getAttribute("role");
		if (role == "presentation") {
		  table._readabilityDataTable = false;
		  continue;
		}
		var datatable = table.getAttribute("datatable");
		if (datatable == "0") {
		  table._readabilityDataTable = false;
		  continue;
		}
		var summary = table.getAttribute("summary");
		if (summary) {
		  table._readabilityDataTable = true;
		  continue;
		}
  
		var caption = table.getElementsByTagName("caption")[0];
		if (caption && caption.childNodes.length > 0) {
		  table._readabilityDataTable = true;
		  continue;
		}
  
		// If the table has a descendant with any of these tags, consider a data table:
		var dataTableDescendants = ["col", "colgroup", "tfoot", "thead", "th"];
		var descendantExists = function(tag) {
		  return !!table.getElementsByTagName(tag)[0];
		};
		if (dataTableDescendants.some(descendantExists)) {
		  this.log("Data table because found data-y descendant");
		  table._readabilityDataTable = true;
		  continue;
		}
  
		// Nested tables indicate a layout table:
		if (table.getElementsByTagName("table")[0]) {
		  table._readabilityDataTable = false;
		  continue;
		}
  
		var sizeInfo = this._getRowAndColumnCount(table);
		if (sizeInfo.rows >= 10 || sizeInfo.columns > 4) {
		  table._readabilityDataTable = true;
		  continue;
		}
		// Now just go by size entirely:
		table._readabilityDataTable = sizeInfo.rows * sizeInfo.columns > 10;
	  }
	},
  
	/* convert images and figures that have properties like data-src into images that can be loaded without JS */
	_fixLazyImages: function (root) {
	  this._forEachNode(this._getAllNodesWithTag(root, ["img", "picture", "figure"]), function (elem) {
		// In some sites (e.g. Kotaku), they put 1px square image as base64 data uri in the src attribute.
		// So, here we check if the data uri is too short, just might as well remove it.
		if (elem.src && this.REGEXPS.b64DataUrl.test(elem.src)) {
		  // Make sure it's not SVG, because SVG can have a meaningful image in under 133 bytes.
		  var parts = this.REGEXPS.b64DataUrl.exec(elem.src);
		  if (parts[1] === "image/svg+xml") {
			return;
		  }
  
		  // Make sure this element has other attributes which contains image.
		  // If it doesn't, then this src is important and shouldn't be removed.
		  var srcCouldBeRemoved = false;
		  for (var i = 0; i < elem.attributes.length; i++) {
			var attr = elem.attributes[i];
			if (attr.name === "src") {
			  continue;
			}
  
			if (/\.(jpg|jpeg|png|webp)/i.test(attr.value)) {
			  srcCouldBeRemoved = true;
			  break;
			}
		  }
  
		  // Here we assume if image is less than 100 bytes (or 133B after encoded to base64)
		  // it will be too small, therefore it might be placeholder image.
		  if (srcCouldBeRemoved) {
			var b64starts = elem.src.search(/base64\s*/i) + 7;
			var b64length = elem.src.length - b64starts;
			if (b64length < 133) {
			  elem.removeAttribute("src");
			}
		  }
		}
  
		// also check for "null" to work around https://github.com/jsdom/jsdom/issues/2580
		if ((elem.src || (elem.srcset && elem.srcset != "null")) && elem.className.toLowerCase().indexOf("lazy") === -1) {
		  return;
		}
  
		for (var j = 0; j < elem.attributes.length; j++) {
		  attr = elem.attributes[j];
		  if (attr.name === "src" || attr.name === "srcset" || attr.name === "alt") {
			continue;
		  }
		  var copyTo = null;
		  if (/\.(jpg|jpeg|png|webp)\s+\d/.test(attr.value)) {
			copyTo = "srcset";
		  } else if (/^\s*\S+\.(jpg|jpeg|png|webp)\S*\s*$/.test(attr.value)) {
			copyTo = "src";
		  }
		  if (copyTo) {
			//if this is an img or picture, set the attribute directly
			if (elem.tagName === "IMG" || elem.tagName === "PICTURE") {
			  elem.setAttribute(copyTo, attr.value);
			} else if (elem.tagName === "FIGURE" && !this._getAllNodesWithTag(elem, ["img", "picture"]).length) {
			  //if the item is a <figure> that does not contain an image or picture, create one and place it inside the figure
			  //see the nytimes-3 testcase for an example
			  var img = this._doc.createElement("img");
			  img.setAttribute(copyTo, attr.value);
			  elem.appendChild(img);
			}
		  }
		}
	  });
	},
  
	_getTextDensity: function(e, tags) {
	  var textLength = this._getInnerText(e, true).length;
	  if (textLength === 0) {
		return 0;
	  }
	  var childrenLength = 0;
	  var children = this._getAllNodesWithTag(e, tags);
	  this._forEachNode(children, (child) => childrenLength += this._getInnerText(child, true).length);
	  return childrenLength / textLength;
	},
  
	/**
	 * Clean an element of all tags of type "tag" if they look fishy.
	 * "Fishy" is an algorithm based on content length, classnames, link density, number of images & embeds, etc.
	 *
	 * @return void
	 **/
	_cleanConditionally: function(e, tag) {
	  if (!this._flagIsActive(this.FLAG_CLEAN_CONDITIONALLY))
		return;
  
	  // Gather counts for other typical elements embedded within.
	  // Traverse backwards so we can remove nodes at the same time
	  // without effecting the traversal.
	  //
	  // TODO: Consider taking into account original contentScore here.
	  this._removeNodes(this._getAllNodesWithTag(e, [tag]), function(node) {
		// First check if this node IS data table, in which case don't remove it.
		var isDataTable = function(t) {
		  return t._readabilityDataTable;
		};
  
		var isList = tag === "ul" || tag === "ol";
		if (!isList) {
		  var listLength = 0;
		  var listNodes = this._getAllNodesWithTag(node, ["ul", "ol"]);
		  this._forEachNode(listNodes, (list) => listLength += this._getInnerText(list).length);
		  isList = listLength / this._getInnerText(node).length > 0.9;
		}
  
		if (tag === "table" && isDataTable(node)) {
		  return false;
		}
  
		// Next check if we're inside a data table, in which case don't remove it as well.
		if (this._hasAncestorTag(node, "table", -1, isDataTable)) {
		  return false;
		}
  
		if (this._hasAncestorTag(node, "code")) {
		  return false;
		}
  
		var weight = this._getClassWeight(node);
  
		this.log("Cleaning Conditionally", node);
  
		var contentScore = 0;
  
		if (weight + contentScore < 0) {
		  return true;
		}
  
		if (this._getCharCount(node, ",") < 10) {
		  // If there are not very many commas, and the number of
		  // non-paragraph elements is more than paragraphs or other
		  // ominous signs, remove the element.
		  var p = node.getElementsByTagName("p").length;
		  var img = node.getElementsByTagName("img").length;
		  var li = node.getElementsByTagName("li").length - 100;
		  var input = node.getElementsByTagName("input").length;
		  var headingDensity = this._getTextDensity(node, ["h1", "h2", "h3", "h4", "h5", "h6"]);
  
		  var embedCount = 0;
		  var embeds = this._getAllNodesWithTag(node, ["object", "embed", "iframe"]);
  
		  for (var i = 0; i < embeds.length; i++) {
			// If this embed has attribute that matches video regex, don't delete it.
			for (var j = 0; j < embeds[i].attributes.length; j++) {
			  if (this._allowedVideoRegex.test(embeds[i].attributes[j].value)) {
				return false;
			  }
			}
  
			// For embed with <object> tag, check inner HTML as well.
			if (embeds[i].tagName === "object" && this._allowedVideoRegex.test(embeds[i].innerHTML)) {
			  return false;
			}
  
			embedCount++;
		  }
  
		  var linkDensity = this._getLinkDensity(node);
		  var contentLength = this._getInnerText(node).length;
  
		  var haveToRemove =
			(img > 1 && p / img < 0.5 && !this._hasAncestorTag(node, "figure")) ||
			(!isList && li > p) ||
			(input > Math.floor(p/3)) ||
			(!isList && headingDensity < 0.9 && contentLength < 25 && (img === 0 || img > 2) && !this._hasAncestorTag(node, "figure")) ||
			(!isList && weight < 25 && linkDensity > 0.2) ||
			(weight >= 25 && linkDensity > 0.5) ||
			((embedCount === 1 && contentLength < 75) || embedCount > 1);
		  // Allow simple lists of images to remain in pages
		  if (isList && haveToRemove) {
			for (var x = 0; x < node.children.length; x++) {
			  let child = node.children[x];
			  // Don't filter in lists with li's that contain more than one child
			  if (child.children.length > 1) {
				return haveToRemove;
			  }
			}
			let li_count = node.getElementsByTagName("li").length;
			// Only allow the list to remain if every li contains an image
			if (img == li_count) {
			  return false;
			}
		  }
		  return haveToRemove;
		}
		return false;
	  });
	},
  
	/**
	 * Clean out elements that match the specified conditions
	 *
	 * @param Element
	 * @param Function determines whether a node should be removed
	 * @return void
	 **/
	_cleanMatchedNodes: function(e, filter) {
	  var endOfSearchMarkerNode = this._getNextNode(e, true);
	  var next = this._getNextNode(e);
	  while (next && next != endOfSearchMarkerNode) {
		if (filter.call(this, next, next.className + " " + next.id)) {
		  next = this._removeAndGetNext(next);
		} else {
		  next = this._getNextNode(next);
		}
	  }
	},
  
	/**
	 * Clean out spurious headers from an Element.
	 *
	 * @param Element
	 * @return void
	**/
	_cleanHeaders: function(e) {
	  let headingNodes = this._getAllNodesWithTag(e, ["h1", "h2"]);
	  this._removeNodes(headingNodes, function(node) {
		let shouldRemove = this._getClassWeight(node) < 0;
		if (shouldRemove) {
		  this.log("Removing header with low class weight:", node);
		}
		return shouldRemove;
	  });
	},
  
	/**
	 * Check if this node is an H1 or H2 element whose content is mostly
	 * the same as the article title.
	 *
	 * @param Element  the node to check.
	 * @return boolean indicating whether this is a title-like header.
	 */
	_headerDuplicatesTitle: function(node) {
	  if (node.tagName != "H1" && node.tagName != "H2") {
		return false;
	  }
	  var heading = this._getInnerText(node, false);
	  this.log("Evaluating similarity of header:", heading, this._articleTitle);
	  return this._textSimilarity(this._articleTitle, heading) > 0.75;
	},
  
	_flagIsActive: function(flag) {
	  return (this._flags & flag) > 0;
	},
  
	_removeFlag: function(flag) {
	  this._flags = this._flags & ~flag;
	},
  
	_isProbablyVisible: function(node) {
	  // Have to null-check node.style and node.className.indexOf to deal with SVG and MathML nodes.
	  return (!node.style || node.style.display != "none")
		&& !node.hasAttribute("hidden")
		//check for "fallback-image" so that wikimedia math images are displayed
		&& (!node.hasAttribute("aria-hidden") || node.getAttribute("aria-hidden") != "true" || (node.className && node.className.indexOf && node.className.indexOf("fallback-image") !== -1));
	},
  
	/**
	 * Runs readability.
	 *
	 * Workflow:
	 *  1. Prep the document by removing script tags, css, etc.
	 *  2. Build readability's DOM tree.
	 *  3. Grab the article content from the current dom tree.
	 *  4. Replace the current DOM tree with the new one.
	 *  5. Read peacefully.
	 *
	 * @return void
	 **/
	parse: function () {
	  // Avoid parsing too large documents, as per configuration option
	  if (this._maxElemsToParse > 0) {
		var numTags = this._doc.getElementsByTagName("*").length;
		if (numTags > this._maxElemsToParse) {
		  throw new Error("Aborting parsing document; " + numTags + " elements found");
		}
	  }
  
	  // Unwrap image from noscript
	  this._unwrapNoscriptImages(this._doc);
  
	  // Extract JSON-LD metadata before removing scripts
	  var jsonLd = this._disableJSONLD ? {} : this._getJSONLD(this._doc);
  
	  // Remove script tags from the document.
	  this._removeScripts(this._doc);
  
	  this._prepDocument();
  
	  var metadata = this._getArticleMetadata(jsonLd);
	  this._articleTitle = metadata.title;
  
	  var articleContent = this._grabArticle();
	  if (!articleContent)
		return null;
  
	  this.log("Grabbed: " + articleContent.innerHTML);
  
	  this._postProcessContent(articleContent);
  
	  // If we haven't found an excerpt in the article's metadata, use the article's
	  // first paragraph as the excerpt. This is used for displaying a preview of
	  // the article's content.
	  if (!metadata.excerpt) {
		var paragraphs = articleContent.getElementsByTagName("p");
		if (paragraphs.length > 0) {
		  metadata.excerpt = paragraphs[0].textContent.trim();
		}
	  }
  
	  var textContent = articleContent.textContent;
	  return {
		title: this._articleTitle,
		byline: metadata.byline || this._articleByline,
		dir: this._articleDir,
		lang: this._articleLang,
		content: this._serializer(articleContent),
		textContent: textContent,
		length: textContent.length,
		excerpt: metadata.excerpt,
		siteName: metadata.siteName || this._articleSiteName
	  };
	}
  };
  
  if (typeof module === "object") {
	/* global module */
	module.exports = Readability;
  }