diff --git a/Libraries/LibWeb/CSS/FontFaceSet.h b/Libraries/LibWeb/CSS/FontFaceSet.h
index 1c84ed10f91..8798650a35e 100644
--- a/Libraries/LibWeb/CSS/FontFaceSet.h
+++ b/Libraries/LibWeb/CSS/FontFaceSet.h
@@ -45,6 +45,8 @@ public:
 
     void resolve_ready_promise();
 
+    void on_set_modified_from_js(Badge<Bindings::FontFaceSetPrototype>) { }
+
 private:
     FontFaceSet(JS::Realm&, GC::Ref<WebIDL::Promise> ready_promise, GC::Ref<JS::Set> set_entries);
 
diff --git a/Meta/Lagom/Tools/CodeGenerators/LibWeb/BindingsGenerator/IDLGenerators.cpp b/Meta/Lagom/Tools/CodeGenerators/LibWeb/BindingsGenerator/IDLGenerators.cpp
index 5bd77c56d93..a11351f5387 100644
--- a/Meta/Lagom/Tools/CodeGenerators/LibWeb/BindingsGenerator/IDLGenerators.cpp
+++ b/Meta/Lagom/Tools/CodeGenerators/LibWeb/BindingsGenerator/IDLGenerators.cpp
@@ -4639,6 +4639,7 @@ JS_DEFINE_NATIVE_FUNCTION(@class_name@::add)
     // What? Which interfaces have a number as their set type?
 
     set->set_add(value_arg);
+    impl->on_set_modified_from_js({});
 
     return impl;
 }
@@ -4660,7 +4661,9 @@ JS_DEFINE_NATIVE_FUNCTION(@class_name@::delete_)
     // FIXME: If value is -0, set value to +0.
     // What? Which interfaces have a number as their set type?
 
-    return set->set_remove(value_arg);
+    auto result = set->set_remove(value_arg);
+    impl->on_set_modified_from_js({});
+    return result;
 }
 )~~~");
         }
@@ -4675,6 +4678,7 @@ JS_DEFINE_NATIVE_FUNCTION(@class_name@::clear)
     GC::Ref<JS::Set> set = impl->set_entries();
 
     set->set_clear();
+    impl->on_set_modified_from_js({});
 
     return JS::js_undefined();
 }