diff --git a/js/gamutable.es6.js b/js/gamutable.es6.js
index a077824..973534f 100644
--- a/js/gamutable.es6.js
+++ b/js/gamutable.es6.js
@@ -35,7 +35,7 @@ jQuery(function () {
 					callback: function () {},
 				});
 			}
-			if (Array.isArray(retour) && retour.message_erreur !== undefined) {
+			if (Array.isArray(retour) && typeof retour.message_erreur !== 'undefined') {
 				alert(retour.message_erreur);
 			}
 		});