diff --git a/components/script/dom/webidls/Node.webidl b/components/script/dom/webidls/Node.webidl
index bb118820237..a595dae3fc0 100644
--- a/components/script/dom/webidls/Node.webidl
+++ b/components/script/dom/webidls/Node.webidl
@@ -35,7 +35,7 @@ interface Node : EventTarget {
   [Pure]
   readonly attribute Element? parentElement;
   boolean hasChildNodes();
-  [Constant]
+  [SameObject]
   readonly attribute NodeList childNodes;
   [Pure]
   readonly attribute Node? firstChild;