Index: gc_core/js/lang_core/gc_engine.js
==================================================================
--- gc_core/js/lang_core/gc_engine.js
+++ gc_core/js/lang_core/gc_engine.js
@@ -11,12 +11,18 @@
     var helpers = require("resource://grammalecte/helpers.js");
     var gc_options = require("resource://grammalecte/${lang}/gc_options.js");
     var gc_rules = require("resource://grammalecte/${lang}/gc_rules.js");
     var cregex = require("resource://grammalecte/${lang}/cregex.js");
     var text = require("resource://grammalecte/text.js");
+    var echo = helpers.echo;
+}
+else if (typeof(console) !== "undefined") {
+    var echo = function (o) { console.log(o); return true; };
 }
-
+else {
+    var echo = function () { return true; }
+}
 
 function capitalizeArray (aArray) {
     // can’t map on user defined function??
     let aNew = [];
     for (let i = 0; i < aArray.length; i = i + 1) {