Use fragment parsing if setting Element.innerHTML

With the new capabilities of parse5 we have to differentiate if we're
parsing a document fragment (i.e. when setting Element.innerHTML) or a
complete document (i.e. the initial parsing stage).

Author: Sebmaster

lib/jsdom/browser/htmltodom.js

@@ -95,6 +95,26 @@ function HtmlToDom(parser) {
 
       return element;
     };
+    this.appendHtmlToDocument = this.appendHtmlToElement;
+
+    if (parser.Parser && parser.TreeAdapters) {
+      this.appendHtmlToElement = function (html, element) {
+
+        if (typeof html !== 'string') {
+          html += '';
+        }
+
+        var instance = new parser.Parser(parser.TreeAdapters.htmlparser2);
+        var dom = instance.parseFragment(html, element);
+        var parsed = dom.children;
+
+        for (var i = 0; i < parsed.length; i++) {
+          setChild(element, parsed[i]);
+        }
+
+        return element;
+      };
+    }
 
   } else if (parser && parser.moduleName == 'HTML5') { /* HTML5 parser */
     this.appendHtmlToElement = function(html, element) {

lib/jsdom/browser/index.js

@@ -499,7 +499,7 @@ var browserAugmentation = exports.browserAugmentation = function(dom, options) {
       }
     }
     if (html !== "" && html != null) {
-      htmltodom.appendHtmlToElement(html, this);
+      htmltodom.appendHtmlToDocument(html, this);
     }
     return html;
   });