Fix fragment parser and regression in innerHTML

lib/DOM/Element.php

@@ -84,7 +84,7 @@ class Element extends \DOMElement {
                 # 3. If the context object is a template element, then let context object be the
                 # template's template contents (a DocumentFragment).
                 if ($this->nodeName === 'template') {
-                    $this->content = $frag;
+                    $this->content = $fragment;
                 }
                 # 4. Replace all with fragment within the context object.
                 else {

lib/Parser.php

@@ -51,13 +51,14 @@ class Parser {
     public static function parseFragment(string $data, ?Document $document = null, ?string $encodingOrContentType = null, ?\DOMElement $fragmentContext = null, ?String $file = null): DocumentFragment {
         // Create the requisite parsing context if none was supplied
         $document = $document ?? new Document;
+        $tempDocument = new Document;
         $fragmentContext = $fragmentContext ?? $document->createElement("div");
         // parse the fragment into the temporary document
-        self::parse($data, $document, $encodingOrContentType, $fragmentContext, $file);
+        self::parse($data, $tempDocument, $encodingOrContentType, $fragmentContext, $file);
         // extract the nodes from the temp document into a fragment
         $fragment = $document->createDocumentFragment();
-        foreach ($document->documentElement->childNodes as $node) {
-            $document->importNode($node, true);
+        foreach ($tempDocument->documentElement->childNodes as $node) {
+            $node = $document->importNode($node, true);
             $fragment->appendChild($node);
         }
         return $fragment;