diff --git a/dom/webidl/HTMLInputElement.webidl b/dom/webidl/HTMLInputElement.webidl
index 13f9f88d9..888a4a2a4 100644
--- a/dom/webidl/HTMLInputElement.webidl
+++ b/dom/webidl/HTMLInputElement.webidl
@@ -88,7 +88,7 @@ interface HTMLInputElement : HTMLElement {
            attribute DOMString defaultValue;
   [Pure, TreatNullAs=EmptyString, SetterThrows]
            attribute DOMString value;
-  [Throws, Pref="dom.experimental_forms"]
+  [Throws, Pref="tenfourfox.dom.forms.date"]
            attribute Date? valueAsDate;
   [Pure, SetterThrows]
            attribute unrestricted double valueAsNumber;