diff --git a/src/stdlib/WebSharper.JavaScript/Ecma.fs b/src/stdlib/WebSharper.JavaScript/Ecma.fs
index ba9fbffa5..4b633e85b 100644
--- a/src/stdlib/WebSharper.JavaScript/Ecma.fs
+++ b/src/stdlib/WebSharper.JavaScript/Ecma.fs
@@ -102,7 +102,7 @@ module Definition =
                 "lastIndexOf" => T<string> * !?T<int>?pos ^-> T<int>
                 "localeCompare" => T<obj> ^-> T<int>
                 "match" => (EcmaRegExp + T<string>) ^-> T<string []>
-                "replace" => (EcmaRegExp + T<string>) * (T<string> + T<Function>) ^-> T<string>
+                "replace" => (EcmaRegExp + T<string>) * (T<string> + (!+ T<obj> ^-> T<string>)) ^-> T<string>
                 "search" => !?EcmaRegExp ^-> T<int>
                 "slice" => T<int>?startPos * !?T<int>?endPos ^-> T<string>
                 "split" =>