diff --git a/Libraries/LibWeb/DOM/AdoptedStyleSheets.cpp b/Libraries/LibWeb/DOM/AdoptedStyleSheets.cpp
index 7e1e611f1c..db57fa2f49 100644
--- a/Libraries/LibWeb/DOM/AdoptedStyleSheets.cpp
+++ b/Libraries/LibWeb/DOM/AdoptedStyleSheets.cpp
@@ -35,7 +35,13 @@ GC::Ref<WebIDL::ObservableArray> create_adopted_style_sheets_list(Document& docu
         document.invalidate_style(DOM::StyleInvalidationReason::AdoptedStyleSheetsList);
         return {};
     });
-    adopted_style_sheets->set_on_delete_an_indexed_value_callback([&document]() -> WebIDL::ExceptionOr<void> {
+    adopted_style_sheets->set_on_delete_an_indexed_value_callback([&document](JS::Value value) -> WebIDL::ExceptionOr<void> {
+        VERIFY(value.is_object());
+        auto& object = value.as_object();
+        VERIFY(is<CSS::CSSStyleSheet>(object));
+        auto& style_sheet = static_cast<CSS::CSSStyleSheet&>(object);
+
+        document.style_computer().unload_fonts_from_sheet(style_sheet);
         document.style_computer().invalidate_rule_cache();
         document.invalidate_style(DOM::StyleInvalidationReason::AdoptedStyleSheetsList);
         return {};
diff --git a/Libraries/LibWeb/WebIDL/ObservableArray.cpp b/Libraries/LibWeb/WebIDL/ObservableArray.cpp
index 0f999f01d6..13c76e6157 100644
--- a/Libraries/LibWeb/WebIDL/ObservableArray.cpp
+++ b/Libraries/LibWeb/WebIDL/ObservableArray.cpp
@@ -48,8 +48,13 @@ JS::ThrowCompletionOr<bool> ObservableArray::internal_set(JS::PropertyKey const&
 
 JS::ThrowCompletionOr<bool> ObservableArray::internal_delete(JS::PropertyKey const& property_key)
 {
-    if (property_key.is_number() && m_on_delete_an_indexed_value)
-        TRY(Bindings::throw_dom_exception_if_needed(vm(), [&] { return m_on_delete_an_indexed_value->function()(); }));
+    if (property_key.is_number() && m_on_delete_an_indexed_value) {
+        auto maybe_value_and_attributes = indexed_properties().get(property_key.as_number());
+        JS::Value deleted_value;
+        if (maybe_value_and_attributes.has_value())
+            deleted_value = maybe_value_and_attributes->value;
+        TRY(Bindings::throw_dom_exception_if_needed(vm(), [&] { return m_on_delete_an_indexed_value->function()(deleted_value); }));
+    }
     return JS::Array::internal_delete(property_key);
 }
 
diff --git a/Libraries/LibWeb/WebIDL/ObservableArray.h b/Libraries/LibWeb/WebIDL/ObservableArray.h
index e3dd4e30a2..f07b9c41bc 100644
--- a/Libraries/LibWeb/WebIDL/ObservableArray.h
+++ b/Libraries/LibWeb/WebIDL/ObservableArray.h
@@ -23,7 +23,7 @@ public:
     virtual JS::ThrowCompletionOr<bool> internal_delete(JS::PropertyKey const& property_key) override;
 
     using SetAnIndexedValueCallbackFunction = Function<ExceptionOr<void>(JS::Value&)>;
-    using DeleteAnIndexedValueCallbackFunction = Function<ExceptionOr<void>()>;
+    using DeleteAnIndexedValueCallbackFunction = Function<ExceptionOr<void>(JS::Value)>;
 
     void set_on_set_an_indexed_value_callback(SetAnIndexedValueCallbackFunction&& callback);
     void set_on_delete_an_indexed_value_callback(DeleteAnIndexedValueCallbackFunction&& callback);