diff --git a/include/class.format.php b/include/class.format.php
index 7ca772fc926ad4c44988b9ef53c9c4adee0ce729..a6dd026d1b40507a45353906620a212a747fcc10 100644
--- a/include/class.format.php
+++ b/include/class.format.php
@@ -161,7 +161,7 @@ class Format {
                 $width);
     }
 
-    static function __html_cleanup($el, $attributes) {
+    static function __html_cleanup($el, $attributes=0) {
         static $eE = array('area'=>1, 'br'=>1, 'col'=>1, 'embed'=>1,
             'hr'=>1, 'img'=>1, 'input'=>1, 'isindex'=>1, 'param'=>1);
         // Clean unexpected class values