diff --git a/core/js/jquery.avatar.js b/core/js/jquery.avatar.js
index dbab032b97..6012eccfad 100644
--- a/core/js/jquery.avatar.js
+++ b/core/js/jquery.avatar.js
@@ -66,7 +66,7 @@
 		}
 
 		// sanitize
-		user = user.replace(/\//g,'');
+		user = String(user).replace(/\//g,'');
 
 		var $div = this;