diff --git a/Libraries/LibWeb/HTML/MessagePort.cpp b/Libraries/LibWeb/HTML/MessagePort.cpp
index e46b7a64182..10b0b920277 100644
--- a/Libraries/LibWeb/HTML/MessagePort.cpp
+++ b/Libraries/LibWeb/HTML/MessagePort.cpp
@@ -438,17 +438,28 @@ void MessagePort::close()
         disentangle();
 }
 
-#undef __ENUMERATE
-#define __ENUMERATE(attribute_name, event_name)                         \
-    void MessagePort::set_##attribute_name(WebIDL::CallbackType* value) \
-    {                                                                   \
-        set_event_handler_attribute(event_name, value);                 \
-    }                                                                   \
-    WebIDL::CallbackType* MessagePort::attribute_name()                 \
-    {                                                                   \
-        return event_handler_attribute(event_name);                     \
-    }
-ENUMERATE_MESSAGE_PORT_EVENT_HANDLERS(__ENUMERATE)
-#undef __ENUMERATE
+// https://html.spec.whatwg.org/multipage/web-messaging.html#handler-messageeventtarget-onmessageerror
+void MessagePort::set_onmessageerror(GC::Ptr<WebIDL::CallbackType> value)
+{
+    set_event_handler_attribute(EventNames::messageerror, value);
+}
+
+// https://html.spec.whatwg.org/multipage/web-messaging.html#handler-messageeventtarget-onmessageerror
+GC::Ptr<WebIDL::CallbackType> MessagePort::onmessageerror()
+{
+    return event_handler_attribute(EventNames::messageerror);
+}
+
+// https://html.spec.whatwg.org/multipage/web-messaging.html#handler-messageeventtarget-onmessage
+void MessagePort::set_onmessage(GC::Ptr<WebIDL::CallbackType> value)
+{
+    set_event_handler_attribute(EventNames::message, value);
+}
+
+// https://html.spec.whatwg.org/multipage/web-messaging.html#handler-messageeventtarget-onmessage
+GC::Ptr<WebIDL::CallbackType> MessagePort::onmessage()
+{
+    return event_handler_attribute(EventNames::message);
+}
 
 }
diff --git a/Libraries/LibWeb/HTML/MessagePort.h b/Libraries/LibWeb/HTML/MessagePort.h
index 8a0968d50ee..881e6da333d 100644
--- a/Libraries/LibWeb/HTML/MessagePort.h
+++ b/Libraries/LibWeb/HTML/MessagePort.h
@@ -18,10 +18,6 @@
 
 namespace Web::HTML {
 
-#define ENUMERATE_MESSAGE_PORT_EVENT_HANDLERS(E) \
-    E(onmessage, HTML::EventNames::message)      \
-    E(onmessageerror, HTML::EventNames::messageerror)
-
 // https://html.spec.whatwg.org/multipage/web-messaging.html#message-ports
 class MessagePort final : public DOM::EventTarget
     , public Bindings::Transferable {
@@ -50,12 +46,11 @@ public:
 
     void close();
 
-#undef __ENUMERATE
-#define __ENUMERATE(attribute_name, event_name)       \
-    void set_##attribute_name(WebIDL::CallbackType*); \
-    WebIDL::CallbackType* attribute_name();
-    ENUMERATE_MESSAGE_PORT_EVENT_HANDLERS(__ENUMERATE)
-#undef __ENUMERATE
+    void set_onmessageerror(GC::Ptr<WebIDL::CallbackType>);
+    GC::Ptr<WebIDL::CallbackType> onmessageerror();
+
+    void set_onmessage(GC::Ptr<WebIDL::CallbackType>);
+    GC::Ptr<WebIDL::CallbackType> onmessage();
 
     // ^Transferable
     virtual WebIDL::ExceptionOr<void> transfer_steps(HTML::TransferDataHolder&) override;