diff --git a/Userland/Libraries/LibWeb/DOM/Node.idl b/Userland/Libraries/LibWeb/DOM/Node.idl
index 9984c4e8b6e..d6c81d5356a 100644
--- a/Userland/Libraries/LibWeb/DOM/Node.idl
+++ b/Userland/Libraries/LibWeb/DOM/Node.idl
@@ -54,6 +54,10 @@ interface Node : EventTarget {
     unsigned short compareDocumentPosition(Node? otherNode);
     boolean contains(Node? other);
 
+    [FIXME] DOMString? lookupPrefix(DOMString? namespace);
+    [FIXME] DOMString? lookupNamespaceURI(DOMString? prefix);
+    [FIXME] boolean isDefaultNamespace(DOMString? namespace);
+
     [ImplementedAs=pre_insert, CEReactions] Node insertBefore(Node node, Node? child);
     [CEReactions] Node appendChild(Node node);
     [CEReactions] Node replaceChild(Node node, Node child);