diff --git a/src/moduleManager.js b/src/moduleManager.js
index 7a87987f..baa9574f 100644
--- a/src/moduleManager.js
+++ b/src/moduleManager.js
@@ -2,7 +2,7 @@ import ab2str from './util/ab2str';
 
 const evalGlobal = eval;
 
-const makeSourceURL = (name) => `${name} | GM Module`.replaceAll(' ', '%20');
+const makeSourceURL = (name) => `${name} | GM Module`.replace(/ /g, '%20');
 
 let goosemodScope = {};