@r3l/app/lib/utils/Readability.js

Relevant App

"use strict";

var _interopRequireDefault = require("@babel/runtime/helpers/interopRequireDefault");

var _toConsumableArray2 = _interopRequireDefault(require("@babel/runtime/helpers/toConsumableArray"));

/*
 * 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
 */

/* eslint-disable */
var root = void 0;

var Node = require("./lib/node");
/**
 * Public constructor.
 * @param {Object}       uri     The URI descriptor object.
 * @param {HTMLDocument} doc     The document to parse.
 * @param {Object}       options The options object.
 */


var Readability = function Readability(uri, doc, options) {
  options = options || {};
  this._uri = uri;
  this._doc = doc;
  this._biggestFrame = false;
  this._articleByline = null;
  this._articleDir = null; // Configureable 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._maxPages = options.maxPages || this.DEFAULT_MAX_PAGES; // Start with all flags set

  this._flags = this.FLAG_STRIP_UNLIKELYS | this.FLAG_WEIGHT_CLASSES | this.FLAG_CLEAN_CONDITIONALLY; // The list of pages we've parsed in this call of readability,
  // for autopaging. As a key store for easier searching.

  this._parsedPages = {}; // A list of the ETag headers of pages we've parsed, in case they happen to match,
  // we'll know it's a duplicate.

  this._pageETags = {}; // Make an AJAX request for each page and append it to the document.

  this._curPageNum = 1; // Control whether log messages are sent to the console

  if (this._debug) {
    function logEl(e) {
      var rv = e.nodeName + ' ';

      if (e.nodeType == e.TEXT_NODE) {
        return rv + '("' + e.textContent + '")';
      }

      var classDesc = e.className && '.' + e.className.replace(/ /g, '.');
      var elDesc = e.id ? '(#' + e.id + classDesc + ')' : classDesc ? '(' + classDesc + ')' : '';
      return rv + elDesc;
    }

    this.log = function () {
      if ('dump' in root) {
        var msg = Array.prototype.map.call(arguments, function (x) {
          return x && x.nodeName ? logEl(x) : x;
        }).join(' ');
        dump('Reader: (Readability) ' + msg + '\n');
      } else if ('console' in root) {
        var _console;

        var args = ['Reader: (Readability) '].concat(arguments);

        (_console = console).log.apply(_console, (0, _toConsumableArray2.default)(args));
      }
    };
  } else {
    this.log = function () {};
  }
};

Readability.prototype = {
  FLAG_STRIP_UNLIKELYS: 0x1,
  FLAG_WEIGHT_CLASSES: 0x2,
  FLAG_CLEAN_CONDITIONALLY: 0x4,
  // 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,
  // The maximum number of pages to loop through before we call
  // it quits and just show a link.
  DEFAULT_MAX_PAGES: 5,
  // Element tags to score by default.
  DEFAULT_TAGS_TO_SCORE: 'section,h2,h3,h4,h5,h6,p,td,pre'.toUpperCase().split(','),
  // All of the regular expressions in use within readability.
  // Defined up here so we don't instantiate them repeatedly in loops.
  REGEXPS: {
    unlikelyCandidates: /banner|combx|comment|community|disqus|extra|foot|header|menu|related|remark|rss|share|shoutbox|sidebar|skyscraper|sponsor|ad-break|agegate|pagination|pager|popup/i,
    okMaybeItsACandidate: /and|article|body|column|main|shadow/i,
    positive: /article|body|content|entry|hentry|main|page|pagination|post|text|blog|story/i,
    negative: /hidden|banner|combx|comment|com-|contact|foot|footer|footnote|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/i,
    replaceFonts: /<(\/?)font[^>]*>/gi,
    normalize: /\s{2,}/g,
    videos: /\/\/(www\.)?(dailymotion|youtube|youtube-nocookie|player\.vimeo)\.com/i,
    nextLink: /(next|weiter|continue|>([^\|]|$)|»([^\|]|$))/i,
    prevLink: /(prev|earl|old|new|<|«)/i,
    whitespace: /^\s*$/,
    hasContent: /\S$/
  },
  DIV_TO_P_ELEMS: ['A', 'BLOCKQUOTE', 'DL', 'DIV', 'IMG', 'OL', 'P', 'PRE', 'TABLE', 'UL', 'SELECT'],
  ALTER_TO_DIV_EXCEPTIONS: ['DIV', 'ARTICLE', 'SECTION', 'P'],

  /**
   * Run any post-process modifications to article content as necessary.
   *
   * @param Element
   * @return void
  * */
  _postProcessContent: function _postProcessContent(articleContent) {
    // Readability cannot open relative uris so we convert them to absolute uris.
    this._fixRelativeUris(articleContent);
  },

  /**
   * 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 _forEachNode(nodeList, fn) {
    return Array.prototype.forEach.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 _someNode(nodeList, fn) {
    return Array.prototype.some.call(nodeList, fn, this);
  },

  /**
   * Concat all nodelists passed as arguments.
   *
   * @return ...NodeList
   * @return Array
   */
  _concatNodeLists: function _concatNodeLists() {
    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 _getAllNodesWithTag(node, tagNames) {
    if (node.querySelectorAll) {
      return node.querySelectorAll(tagNames.join(','));
    }

    return [].concat.apply([], tagNames.map(function (tag) {
      return node.getElementsByTagName(tag);
    }));
  },

  /**
   * Converts each <a> and <img> uri in the given element to an absolute URI.
   *
   * @param Element
   * @return void
   */
  _fixRelativeUris: function _fixRelativeUris(articleContent) {
    var scheme = this._uri.scheme;
    var prePath = this._uri.prePath;
    var pathBase = this._uri.pathBase;

    function toAbsoluteURI(uri) {
      // If this is already an absolute URI, return it.
      if (/^[a-zA-Z][a-zA-Z0-9\+\-\.]*:/.test(uri)) {
        return uri;
      } // Scheme-rooted relative URI.


      if (uri.substr(0, 2) == '//') {
        return scheme + '://' + uri.substr(2);
      } // Prepath-rooted relative URI.


      if (uri[0] == '/') {
        return prePath + uri;
      } // Dotslash relative URI.


      if (uri.indexOf('./') === 0) {
        return pathBase + uri.slice(2);
      } // Standard relative URI; add entire path. pathBase already includes a
      // trailing "/".


      return pathBase + uri;
    }

    var links = articleContent.getElementsByTagName('a');

    this._forEachNode(links, function (link) {
      var href = link.getAttribute('href');

      if (href) {
        // Replace links with javascript: URIs with text content, since
        // they won't work after scripts have been removed from the page.
        if (href.indexOf('javascript:') === 0) {
          var text = this._doc.createTextNode(link.textContent);

          link.parentNode.replaceChild(text, link);
        } else {
          link.setAttribute('href', toAbsoluteURI(href));
        }
      }
    });

    var imgs = articleContent.getElementsByTagName('img');

    this._forEachNode(imgs, function (img) {
      var src = img.getAttribute('src');

      if (src) {
        img.setAttribute('src', toAbsoluteURI(src));
      }
    });
  },

  /**
   * Get the article title as an H1.
   *
   * @return void
   * */
  _getArticleTitle: function _getArticleTitle() {
    var doc = this._doc;
    var curTitle = '';
    var origTitle = '';

    try {
      curTitle = origTitle = doc.title; // 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) {}

    if (curTitle.match(/ [\|\-] /)) {
      curTitle = origTitle.replace(/(.*)[\|\-] .*/gi, '$1');

      if (curTitle.split(' ').length < 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 match = this._someNode(headings, function (heading) {
        return heading.textContent === curTitle;
      }); // 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 (curTitle.split(' ').length < 3) {
          curTitle = origTitle.substring(origTitle.indexOf(':') + 1);
        }
      }
    } 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();

    if (curTitle.split(' ').length <= 4) {
      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 _prepDocument() {
    var doc = this._doc; // Remove all style tags in head

    this._forEachNode(doc.getElementsByTagName('style'), function (styleNode) {
      styleNode.parentNode.removeChild(styleNode);
    });

    if (doc.body) {
      this._replaceBrs(doc.body);
    }

    this._forEachNode(doc.getElementsByTagName('font'), function (fontNode) {
      this._setNodeTag(fontNode, 'SPAN');
    });
  },

  /**
   * Finds the next element, starting from the given node, and ignoring
   * whitespace in between. If the given node is an element, the same node is
   * returned.
   */
  _nextElement: function _nextElement(node) {
    var next = node;

    while (next && next.nodeType != Node.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 _replaceBrs(elem) {
    this._forEachNode(elem.getElementsByTagName('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 element
      // or non-whitespace. This leaves behind the first <br> in the chain
      // (which will be replaced with a <p> later).

      while ((next = this._nextElement(next)) && next.tagName == 'BR') {
        replaced = true;
        var sibling = next.nextSibling;
        next.parentNode.removeChild(next);
        next = sibling;
      } // 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._nextElement(next);

            if (nextElem && nextElem.tagName == 'BR') {
              break;
            }
          } // Otherwise, make this node a child of the new <p>.


          var sibling = next.nextSibling;
          p.appendChild(next);
          next = sibling;
        }
      }
    });
  },
  _setNodeTag: function _setNodeTag(node, tag) {
    this.log('_setNodeTag', node, tag);

    if (node.__JSDOMParser__) {
      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++) {
      replacement.setAttribute(node.attributes[i].name, node.attributes[i].value);
    }

    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 _prepArticle(articleContent) {
    this._cleanStyles(articleContent); // Clean out junk from the article content


    this._cleanConditionally(articleContent, 'form');

    this._clean(articleContent, 'object');

    this._clean(articleContent, 'embed');

    this._clean(articleContent, 'h1');

    this._clean(articleContent, 'footer'); // If there is only one h2, they are probably using it as a header
    // and not a subheader, so remove it since we already have a header.


    if (articleContent.getElementsByTagName('h2').length === 1) {
      this._clean(articleContent, 'h2');
    }

    this._clean(articleContent, 'iframe');

    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'); // Remove extra paragraphs


    this._forEachNode(articleContent.getElementsByTagName('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;

      if (totalCount === 0 && !this._getInnerText(paragraph, false)) {
        paragraph.parentNode.removeChild(paragraph);
      }
    });

    this._forEachNode(articleContent.getElementsByTagName('br'), function (br) {
      var next = this._nextElement(br.nextSibling);

      if (next && next.tagName == 'P') {
        br.parentNode.removeChild(br);
      }
    });
  },

  /**
   * 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 _initializeNode(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 _removeAndGetNext(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 _getNextNode(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;
  },

  /**
   * Like _getNextNode, but for DOM implementations with no
   * firstElementChild/nextElementSibling functionality...
   */
  _getNextNodeNoElementProperties: function _getNextNodeNoElementProperties(node, ignoreSelfAndKids) {
    function nextSiblingEl(n) {
      do {
        n = n.nextSibling;
      } while (n && n.nodeType !== n.ELEMENT_NODE);

      return n;
    } // First check for kids if those aren't being ignored


    if (!ignoreSelfAndKids && node.children[0]) {
      return node.children[0];
    } // Then for siblings...


    var next = nextSiblingEl(node);

    if (next) {
      return next;
    } // 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;

      if (node) {
        next = nextSiblingEl(node);
      }
    } while (node && !next);

    return node && next;
  },
  _checkByline: function _checkByline(node, matchString) {
    if (this._articleByline) {
      return false;
    }

    if (node.getAttribute !== undefined) {
      var rel = node.getAttribute('rel');
    }

    if ((rel === 'author' || this.REGEXPS.byline.test(matchString)) && this._isValidByline(node.textContent)) {
      this._articleByline = node.textContent.trim();
      return true;
    }

    return false;
  },
  _getNodeAncestors: function _getNodeAncestors(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 _grabArticle(page) {
    this.log('**** grabArticle ****');
    var doc = this._doc;
    var isPaging = page !== null;
    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; // Check if any "dir" is set on the toplevel document element

    this._articleDir = doc.documentElement.getAttribute('dir');

    while (true) {
      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;

      while (node) {
        var matchString = node.className + ' ' + node.id; // 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;
        } // Remove unlikely candidates


        if (stripUnlikelyCandidates) {
          if (this.REGEXPS.unlikelyCandidates.test(matchString) && !this.REGEXPS.okMaybeItsACandidate.test(matchString) && node.tagName !== 'BODY' && node.tagName !== 'A') {
            this.log('Removing unlikely candidate - ' + matchString);
            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') {
          // 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._hasSinglePInsideElement(node)) {
            var newNode = node.children[0];
            node.parentNode.replaceChild(newNode, node);
            node = newNode;
          } else if (!this._hasChildBlockElement(node)) {
            node = this._setNodeTag(node, 'P');
            elementsToScore.push(node);
          } else {
            // EXPERIMENTAL
            this._forEachNode(node.childNodes, function (childNode) {
              if (childNode.nodeType === Node.TEXT_NODE) {
                var p = doc.createElement('p');
                p.textContent = childNode.textContent;
                p.style.display = 'inline';
                p.className = 'readability-styled';
                node.replaceChild(p, childNode);
              }
            });
          }
        }

        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, 3);

        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(',').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) {
            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


          var scoreDivider = level === 0 ? 1 : level === 1 ? 2 : 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; // 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:

        var kids = page.childNodes;

        while (kids.length) {
          this.log('Moving child out:', kids[0]);
          topCandidate.appendChild(kids[0]);
        }

        page.appendChild(topCandidate);

        this._initializeNode(topCandidate);
      } else if (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.
        var parentOfTopCandidate = topCandidate.parentNode;
        var lastScore = topCandidate.readability.contentScore; // The scores shouldn't get too low.

        var scoreThreshold = lastScore / 3;

        while (parentOfTopCandidate && parentOfTopCandidate.readability) {
          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;
        }
      } // 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);
      var siblings = topCandidate.parentNode.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 && 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); // 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 (this._curPageNum === 1) {
        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';
          var children = articleContent.childNodes;

          while (children.length) {
            div.appendChild(children[0]);
          }

          articleContent.appendChild(div);
        }
      }

      if (this._debug) {
        this.log('Article content after paging: ' + articleContent.innerHTML);
      } // 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.


      if (this._getInnerText(articleContent, true).length < 500) {
        page.innerHTML = pageCacheHtml;

        if (this._flagIsActive(this.FLAG_STRIP_UNLIKELYS)) {
          this._removeFlag(this.FLAG_STRIP_UNLIKELYS);
        } else if (this._flagIsActive(this.FLAG_WEIGHT_CLASSES)) {
          this._removeFlag(this.FLAG_WEIGHT_CLASSES);
        } else if (this._flagIsActive(this.FLAG_CLEAN_CONDITIONALLY)) {
          this._removeFlag(this.FLAG_CLEAN_CONDITIONALLY);
        } else {
          return null;
        }
      } else {
        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 _isValidByline(byline) {
    if (typeof byline === 'string' || byline instanceof String) {
      byline = byline.trim();
      return byline.length > 0 && byline.length < 100;
    }

    return false;
  },

  /**
   * Attempts to get excerpt and byline metadata for the article.
   *
   * @return Object with optional "excerpt" and "byline" properties
   */
  _getArticleMetadata: function _getArticleMetadata() {
    var metadata = {};
    var values = {};

    var metaElements = this._doc.getElementsByTagName('meta'); // Match "description", or Twitter's "twitter:description" (Cards)
    // in name attribute.


    var namePattern = /^\s*((twitter)\s*:\s*)?(description|title)\s*$/gi; // Match Facebook's Open Graph title & description properties.

    var propertyPattern = /^\s*og\s*:\s*(description|title)\s*$/gi; // Find description tags.

    this._forEachNode(metaElements, function (element) {
      var elementName = element.getAttribute('name');
      var elementProperty = element.getAttribute('property');

      if ([elementName, elementProperty].indexOf('author') !== -1) {
        metadata.byline = element.getAttribute('content');
        return;
      }

      var name = null;

      if (namePattern.test(elementName)) {
        name = elementName;
      } else if (propertyPattern.test(elementProperty)) {
        name = elementProperty;
      }

      if (name) {
        var content = element.getAttribute('content');

        if (content) {
          // Convert to lowercase and remove any whitespace
          // so we can match below.
          name = name.toLowerCase().replace(/\s/g, '');
          values[name] = content.trim();
        }
      }
    });

    if ('description' in values) {
      metadata.excerpt = values.description;
    } else if ('og:description' in values) {
      // Use facebook open graph description.
      metadata.excerpt = values['og:description'];
    } else if ('twitter:description' in values) {
      // Use twitter cards description.
      metadata.excerpt = values['twitter:description'];
    }

    if ('og:title' in values) {
      // Use facebook open graph title.
      metadata.title = values['og:title'];
    } else if ('twitter:title' in values) {
      // Use twitter cards title.
      metadata.title = values['twitter:title'];
    }

    return metadata;
  },

  /**
   * Removes script tags from the document.
   *
   * @param Element
  * */
  _removeScripts: function _removeScripts(doc) {
    this._forEachNode(doc.getElementsByTagName('script'), function (scriptNode) {
      scriptNode.nodeValue = '';
      scriptNode.removeAttribute('src');

      if (scriptNode.parentNode) {
        scriptNode.parentNode.removeChild(scriptNode);
      }
    });

    this._forEachNode(doc.getElementsByTagName('noscript'), function (noscriptNode) {
      if (noscriptNode.parentNode) {
        noscriptNode.parentNode.removeChild(noscriptNode);
      }
    });
  },

  /**
   * Check if this node has only whitespace and a single P element
   * Returns false if the DIV node contains non-empty text nodes
   * or if it contains no P or more than 1 element.
   *
   * @param Element
  * */
  _hasSinglePInsideElement: function _hasSinglePInsideElement(element) {
    // There should be exactly 1 element child which is a P:
    if (element.children.length != 1 || element.children[0].tagName !== 'P') {
      return false;
    } // And there should be no text nodes with real content


    return !this._someNode(element.childNodes, function (node) {
      return node.nodeType === Node.TEXT_NODE && this.REGEXPS.hasContent.test(node.textContent);
    });
  },

  /**
   * Determine whether element has any children block level elements.
   *
   * @param Element
   */
  _hasChildBlockElement: function _hasChildBlockElement(element) {
    return this._someNode(element.childNodes, function (node) {
      return this.DIV_TO_P_ELEMS.indexOf(node.tagName) !== -1 || this._hasChildBlockElement(node);
    });
  },

  /**
   * 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 _getInnerText(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 _getCharCount(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 _cleanStyles(e) {
    e = e || this._doc;

    if (!e) {
      return;
    }

    var cur = e.firstChild; // Remove any root styles, if we're able.

    if (typeof e.removeAttribute === 'function' && e.className !== 'readability-styled') {
      e.removeAttribute('style');
    } // Go until there are no more child nodes


    while (cur !== null) {
      if (cur.nodeType === cur.ELEMENT_NODE) {
        // Remove style attribute(s) :
        if (cur.className !== 'readability-styled') {
          cur.removeAttribute('style');
        }

        this._cleanStyles(cur);
      }

      cur = cur.nextSibling;
    }
  },

  /**
   * 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 _getLinkDensity(element) {
    var textLength = this._getInnerText(element).length;

    if (textLength === 0) {
      return;
    }

    var linkLength = 0; // XXX implement _reduceNodeList?

    this._forEachNode(element.getElementsByTagName('a'), function (linkNode) {
      linkLength += this._getInnerText(linkNode).length;
    });

    return linkLength / textLength;
  },

  /**
   * Find a cleaned up version of the current URL, to use for comparing links for possible next-pageyness.
   *
   * @author Dan Lacy
   * @return string the base url
  * */
  _findBaseUrl: function _findBaseUrl() {
    var uri = this._uri;
    var noUrlParams = uri.path.split('?')[0];
    var urlSlashes = noUrlParams.split('/').reverse();
    var cleanedSegments = [];
    var possibleType = '';

    for (var i = 0, slashLen = urlSlashes.length; i < slashLen; i += 1) {
      var segment = urlSlashes[i]; // Split off and save anything that looks like a file type.

      if (segment.indexOf('.') !== -1) {
        possibleType = segment.split('.')[1]; // If the type isn't alpha-only, it's probably not actually a file extension.

        if (!possibleType.match(/[^a-zA-Z]/)) {
          segment = segment.split('.')[0];
        }
      } // EW-CMS specific segment replacement. Ugly.
      // Example: http://www.ew.com/ew/article/0,,20313460_20369436,00.html


      if (segment.indexOf(',00') !== -1) {
        segment = segment.replace(',00', '');
      } // If our first or second segment has anything looking like a page number, remove it.


      if (segment.match(/((_|-)?p[a-z]*|(_|-))[0-9]{1,2}$/i) && (i === 1 || i === 0)) {
        segment = segment.replace(/((_|-)?p[a-z]*|(_|-))[0-9]{1,2}$/i, '');
      }

      var del = false; // If this is purely a number, and it's the first or second segment,
      // it's probably a page number. Remove it.

      if (i < 2 && segment.match(/^\d{1,2}$/)) {
        del = true;
      } // If this is the first segment and it's just "index", remove it.


      if (i === 0 && segment.toLowerCase() === 'index') {
        del = true;
      } // If our first or second segment is smaller than 3 characters,
      // and the first segment was purely alphas, remove it.


      if (i < 2 && segment.length < 3 && !urlSlashes[0].match(/[a-z]/i)) {
        del = true;
      } // If it's not marked for deletion, push it to cleanedSegments.


      if (!del) {
        cleanedSegments.push(segment);
      }
    } // This is our final, cleaned, base article URL.


    return uri.scheme + '://' + uri.host + cleanedSegments.reverse().join('/');
  },

  /**
   * Look for any paging links that may occur within the document.
   *
   * @param body
   * @return object (array)
  * */
  _findNextPageLink: function _findNextPageLink(elem) {
    var uri = this._uri;
    var possiblePages = {};
    var allLinks = elem.getElementsByTagName('a');

    var articleBaseUrl = this._findBaseUrl(); // Loop through all links, looking for hints that they may be next-page links.
    // Things like having "page" in their textContent, className or id, or being a child
    // of a node with a page-y className or id.
    //
    // Also possible: levenshtein distance? longest common subsequence?
    //
    // After we do that, assign each page a score, and


    for (var i = 0, il = allLinks.length; i < il; i += 1) {
      var link = allLinks[i];
      var linkHref = allLinks[i].href.replace(/#.*$/, '').replace(/\/$/, ''); // If we've already seen this page, ignore it.

      if (linkHref === '' || linkHref === articleBaseUrl || linkHref === uri.spec || linkHref in this._parsedPages) {
        continue;
      } // If it's on a different domain, skip it.


      if (uri.host !== linkHref.split(/\/+/g)[1]) {
        continue;
      }

      var linkText = this._getInnerText(link); // If the linkText looks like it's not the next page, skip it.


      if (linkText.match(this.REGEXPS.extraneous) || linkText.length > 25) {
        continue;
      } // If the leftovers of the URL after removing the base URL don't contain
      // any digits, it's certainly not a next page link.


      var linkHrefLeftover = linkHref.replace(articleBaseUrl, '');

      if (!linkHrefLeftover.match(/\d/)) {
        continue;
      }

      if (!(linkHref in possiblePages)) {
        possiblePages[linkHref] = {
          score: 0,
          linkText: linkText,
          href: linkHref
        };
      } else {
        possiblePages[linkHref].linkText += ' | ' + linkText;
      }

      var linkObj = possiblePages[linkHref]; // If the articleBaseUrl isn't part of this URL, penalize this link. It could
      // still be the link, but the odds are lower.
      // Example: http://www.actionscript.org/resources/articles/745/1/JavaScript-and-VBScript-Injection-in-ActionScript-3/Page1.html

      if (linkHref.indexOf(articleBaseUrl) !== 0) {
        linkObj.score -= 25;
      }

      var linkData = linkText + ' ' + link.className + ' ' + link.id;

      if (linkData.match(this.REGEXPS.nextLink)) {
        linkObj.score += 50;
      }

      if (linkData.match(/pag(e|ing|inat)/i)) {
        linkObj.score += 25;
      }

      if (linkData.match(/(first|last)/i)) {
        // -65 is enough to negate any bonuses gotten from a > or » in the text,
        // If we already matched on "next", last is probably fine.
        // If we didn't, then it's bad. Penalize.
        if (!linkObj.linkText.match(this.REGEXPS.nextLink)) {
          linkObj.score -= 65;
        }
      }

      if (linkData.match(this.REGEXPS.negative) || linkData.match(this.REGEXPS.extraneous)) {
        linkObj.score -= 50;
      }

      if (linkData.match(this.REGEXPS.prevLink)) {
        linkObj.score -= 200;
      } // If a parentNode contains page or paging or paginat


      var parentNode = link.parentNode;
      var positiveNodeMatch = false;
      var negativeNodeMatch = false;

      while (parentNode) {
        var parentNodeClassAndId = parentNode.className + ' ' + parentNode.id;

        if (!positiveNodeMatch && parentNodeClassAndId && parentNodeClassAndId.match(/pag(e|ing|inat)/i)) {
          positiveNodeMatch = true;
          linkObj.score += 25;
        }

        if (!negativeNodeMatch && parentNodeClassAndId && parentNodeClassAndId.match(this.REGEXPS.negative)) {
          // If this is just something like "footer", give it a negative.
          // If it's something like "body-and-footer", leave it be.
          if (!parentNodeClassAndId.match(this.REGEXPS.positive)) {
            linkObj.score -= 25;
            negativeNodeMatch = true;
          }
        }

        parentNode = parentNode.parentNode;
      } // If the URL looks like it has paging in it, add to the score.
      // Things like /page/2/, /pagenum/2, ?p=3, ?page=11, ?pagination=34


      if (linkHref.match(/p(a|g|ag)?(e|ing|ination)?(=|\/)[0-9]{1,2}/i) || linkHref.match(/(page|paging)/i)) {
        linkObj.score += 25;
      } // If the URL contains negative values, give a slight decrease.


      if (linkHref.match(this.REGEXPS.extraneous)) {
        linkObj.score -= 15;
      }
      /**
       * Minor punishment to anything that doesn't match our current URL.
       * NOTE: I'm finding this to cause more harm than good where something is exactly 50 points.
       *     Dan, can you show me a counterexample where this is necessary?
       * if (linkHref.indexOf(window.location.href) !== 0) {
       *  linkObj.score -= 1;
       * }
      * */
      // If the link text can be parsed as a number, give it a minor bonus, with a slight
      // bias towards lower numbered pages. This is so that pages that might not have 'next'
      // in their text can still get scored, and sorted properly by score.


      var linkTextAsNumber = parseInt(linkText, 10);

      if (linkTextAsNumber) {
        // Punish 1 since we're either already there, or it's probably
        // before what we want anyways.
        if (linkTextAsNumber === 1) {
          linkObj.score -= 10;
        } else {
          linkObj.score += Math.max(0, 10 - linkTextAsNumber);
        }
      }
    } // Loop thrugh all of our possible pages from above and find our top
    // candidate for the next page URL. Require at least a score of 50, which
    // is a relatively high confidence that this page is the next link.


    var topPage = null;

    for (var page in possiblePages) {
      if (possiblePages.hasOwnProperty(page)) {
        if (possiblePages[page].score >= 50 && (!topPage || topPage.score < possiblePages[page].score)) {
          topPage = possiblePages[page];
        }
      }
    }

    if (topPage) {
      var nextHref = topPage.href.replace(/\/$/, '');
      this.log('NEXT PAGE IS ' + nextHref);
      this._parsedPages[nextHref] = true;
      return nextHref;
    }

    return null;
  },
  _successfulRequest: function _successfulRequest(request) {
    return request.status >= 200 && request.status < 300 || request.status === 304 || request.status === 0 && request.responseText;
  },
  _ajax: function _ajax(url, options) {
    var request = new XMLHttpRequest();

    function respondToReadyState(readyState) {
      if (request.readyState === 4) {
        if (this._successfulRequest(request)) {
          if (options.success) {
            options.success(request);
          }
        } else if (options.error) {
          options.error(request);
        }
      }
    }

    if (typeof options === 'undefined') {
      options = {};
    }

    request.onreadystatechange = respondToReadyState;
    request.open('get', url, true);
    request.setRequestHeader('Accept', 'text/html');

    try {
      request.send(options.postBody);
    } catch (e) {
      if (options.error) {
        options.error();
      }
    }

    return request;
  },
  _appendNextPage: function _appendNextPage(nextPageLink) {
    var doc = this._doc;
    this._curPageNum += 1;
    var articlePage = doc.createElement('DIV');
    articlePage.id = 'readability-page-' + this._curPageNum;
    articlePage.className = 'page';
    articlePage.innerHTML = '<p class="page-separator" title="Page ' + this._curPageNum + '">&sect;</p>';
    doc.getElementById('readability-content').appendChild(articlePage);

    if (this._curPageNum > this._maxPages) {
      var nextPageMarkup = "<di