code: function (parent, html) {
      if (!testDocument) {
        testDocument = document.implementation.createHTMLDocument();
      }
      var testElement = parent.namespaceURI === HTML_NAMESPACE$1 ? testDocument.createElement(parent.tagName) : testDocument.createElementNS(parent.namespaceURI, parent.tagName);
      testElement.innerHTML = html;
      return testElement.innerHTML;
    }
docs: Parse the HTML and read it back to normalize the HTML string so that it can be used for comparison.