diff --git a/Libraries/LibWeb/DOM/DocumentObserver.cpp b/Libraries/LibWeb/DOM/DocumentObserver.cpp
index d5cee5da4f2..d38a17cecf3 100644
--- a/Libraries/LibWeb/DOM/DocumentObserver.cpp
+++ b/Libraries/LibWeb/DOM/DocumentObserver.cpp
@@ -12,7 +12,7 @@ namespace Web::DOM {
 
 GC_DEFINE_ALLOCATOR(DocumentObserver);
 
-DocumentObserver::DocumentObserver(JS::Realm& realm, DOM::Document& document)
+DocumentObserver::DocumentObserver(JS::Realm& realm, Document& document)
     : Bindings::PlatformObject(realm)
     , m_document(document)
 {
@@ -37,6 +37,14 @@ void DocumentObserver::finalize()
     m_document->unregister_document_observer({}, *this);
 }
 
+void DocumentObserver::set_document(GC::Ref<Document> document)
+{
+    VERIFY(document != m_document);
+    m_document->unregister_document_observer({}, *this);
+    m_document = document;
+    document->register_document_observer({}, *this);
+}
+
 void DocumentObserver::set_document_became_active(Function<void()> callback)
 {
     if (callback)
diff --git a/Libraries/LibWeb/DOM/DocumentObserver.h b/Libraries/LibWeb/DOM/DocumentObserver.h
index 9ba4ca2faeb..32187d08e3d 100644
--- a/Libraries/LibWeb/DOM/DocumentObserver.h
+++ b/Libraries/LibWeb/DOM/DocumentObserver.h
@@ -38,13 +38,16 @@ public:
     [[nodiscard]] GC::Ptr<GC::Function<void(bool)>> document_page_showing_observer() const { return m_document_page_showing_observer; }
     void set_document_page_showing_observer(Function<void(bool)>);
 
+    GC::Ref<Document> document() { return m_document; }
+    void set_document(GC::Ref<Document>);
+
 private:
-    explicit DocumentObserver(JS::Realm&, DOM::Document&);
+    explicit DocumentObserver(JS::Realm&, Document&);
 
     virtual void visit_edges(Cell::Visitor&) override;
     virtual void finalize() override;
 
-    GC::Ref<DOM::Document> m_document;
+    GC::Ref<Document> m_document;
     GC::Ptr<GC::Function<void()>> m_document_became_active;
     GC::Ptr<GC::Function<void()>> m_document_became_inactive;
     GC::Ptr<GC::Function<void()>> m_document_completely_loaded;