code: function (html, url) {
        this.html = html;
        var doc = this.doc = new Document(url);
        this.readChildren(doc);
  
        // If this is an HTML document, remove root-level children except for the
        // <html> node
        if (doc.documentElement) {
          for (var i = doc.childNodes.length; --i >= 0;) {
            var child = doc.childNodes[i];
            if (child !== doc.documentElement) {
              doc.removeChild(child);
            }
          }
        }
  
        return doc;
      }
docs: Parses an HTML string and returns a JS implementation of the Document.