--- a/dom/base/AnonymousContent.cpp
+++ b/dom/base/AnonymousContent.cpp
@@ -154,24 +154,24 @@ AnonymousContent::SetAnimationForElement
   return element->Animate(aContext, aKeyframes, aOptions, aRv);
 }
 
 Element*
 AnonymousContent::GetElementById(const nsAString& aElementId)
 {
   // This can be made faster in the future if needed.
   nsCOMPtr<nsIAtom> elementId = NS_Atomize(aElementId);
-  for (nsIContent* kid = mContentNode->GetFirstChild(); kid;
-       kid = kid->GetNextNode(mContentNode)) {
-    if (!kid->IsElement()) {
+  for (nsIContent* node = mContentNode; node;
+       node = node->GetNextNode(mContentNode)) {
+    if (!node->IsElement()) {
       continue;
     }
-    nsIAtom* id = kid->AsElement()->GetID();
+    nsIAtom* id = node->AsElement()->GetID();
     if (id && id == elementId) {
-      return kid->AsElement();
+      return node->AsElement();
     }
   }
   return nullptr;
 }
 
 bool
 AnonymousContent::WrapObject(JSContext* aCx,
                              JS::Handle<JSObject*> aGivenProto,