diff --git a/Userland/Libraries/LibWeb/DOM/NamedNodeMap.cpp b/Userland/Libraries/LibWeb/DOM/NamedNodeMap.cpp
index cb15e840dc..6c0a2a798d 100644
--- a/Userland/Libraries/LibWeb/DOM/NamedNodeMap.cpp
+++ b/Userland/Libraries/LibWeb/DOM/NamedNodeMap.cpp
@@ -87,9 +87,14 @@ Attr const* NamedNodeMap::get_named_item(StringView qualified_name) const
 }
 
 // https://dom.spec.whatwg.org/#dom-namednodemap-getnameditemns
-Attr const* NamedNodeMap::get_named_item_ns(StringView namespace_, StringView local_name) const
+Attr const* NamedNodeMap::get_named_item_ns(Optional<String> const& namespace_, StringView local_name) const
 {
-    return get_attribute_ns(namespace_, local_name);
+    // FIXME: This conversion is quite ugly.
+    StringView namespace_view;
+    if (namespace_.has_value())
+        namespace_view = namespace_->bytes_as_string_view();
+
+    return get_attribute_ns(namespace_view, local_name);
 }
 
 // https://dom.spec.whatwg.org/#dom-namednodemap-setnameditem
@@ -119,10 +124,15 @@ WebIDL::ExceptionOr<Attr const*> NamedNodeMap::remove_named_item(StringView qual
 }
 
 // https://dom.spec.whatwg.org/#dom-namednodemap-removenameditemns
-WebIDL::ExceptionOr<Attr const*> NamedNodeMap::remove_named_item_ns(StringView namespace_, StringView local_name)
+WebIDL::ExceptionOr<Attr const*> NamedNodeMap::remove_named_item_ns(Optional<String> const& namespace_, StringView local_name)
 {
+    // FIXME: This conversion is quite ugly.
+    StringView namespace_view;
+    if (namespace_.has_value())
+        namespace_view = namespace_->bytes_as_string_view();
+
     // 1. Let attr be the result of removing an attribute given namespace, localName, and element.
-    auto const* attribute = remove_attribute_ns(namespace_, local_name);
+    auto const* attribute = remove_attribute_ns(namespace_view, local_name);
 
     // 2. If attr is null, then throw a "NotFoundError" DOMException.
     if (!attribute)
diff --git a/Userland/Libraries/LibWeb/DOM/NamedNodeMap.h b/Userland/Libraries/LibWeb/DOM/NamedNodeMap.h
index 7a7e46d21e..cd26b10425 100644
--- a/Userland/Libraries/LibWeb/DOM/NamedNodeMap.h
+++ b/Userland/Libraries/LibWeb/DOM/NamedNodeMap.h
@@ -36,11 +36,11 @@ public:
     // Methods defined by the spec for JavaScript:
     Attr const* item(u32 index) const;
     Attr const* get_named_item(StringView qualified_name) const;
-    Attr const* get_named_item_ns(StringView namespace_, StringView local_name) const;
+    Attr const* get_named_item_ns(Optional<String> const& namespace_, StringView local_name) const;
     WebIDL::ExceptionOr<JS::GCPtr<Attr>> set_named_item(Attr& attribute);
     WebIDL::ExceptionOr<JS::GCPtr<Attr>> set_named_item_ns(Attr& attribute);
     WebIDL::ExceptionOr<Attr const*> remove_named_item(StringView qualified_name);
-    WebIDL::ExceptionOr<Attr const*> remove_named_item_ns(StringView namespace_, StringView local_name);
+    WebIDL::ExceptionOr<Attr const*> remove_named_item_ns(Optional<String> const& namespace_, StringView local_name);
 
     // Methods defined by the spec for internal use:
     Attr* get_attribute(StringView qualified_name, size_t* item_index = nullptr);
diff --git a/Userland/Libraries/LibWeb/DOM/NamedNodeMap.idl b/Userland/Libraries/LibWeb/DOM/NamedNodeMap.idl
index 2bfdadcf5d..cf52b16552 100644
--- a/Userland/Libraries/LibWeb/DOM/NamedNodeMap.idl
+++ b/Userland/Libraries/LibWeb/DOM/NamedNodeMap.idl
@@ -1,6 +1,6 @@
 #import <DOM/Attr.idl>
 
-[Exposed=Window, LegacyUnenumerableNamedProperties, UseDeprecatedAKString]
+[Exposed=Window, LegacyUnenumerableNamedProperties]
 interface NamedNodeMap {
     readonly attribute unsigned long length;