diff --git a/content/handlers/javascript/duktape/Window.bnd b/content/handlers/javascript/duktape/Window.bnd
index 39c58c41d..b2e8166a6 100644
--- a/content/handlers/javascript/duktape/Window.bnd
+++ b/content/handlers/javascript/duktape/Window.bnd
@@ -265,6 +265,7 @@ prototype Window()
 	EXPOSE(encodeURIComponent);
 	EXPOSE(NaN);
 	EXPOSE(isNaN);
+	EXPOSE(isFinite);
 #undef EXPOSE
 	/* Add s3kr1t method to close the compartment */
 	duk_dup(ctx, 0);