diff --git a/module/api/ui/editstruct.html.php b/module/api/ui/editstruct.html.php
index ac5c1ff8f4..b54343be41 100644
--- a/module/api/ui/editstruct.html.php
+++ b/module/api/ui/editstruct.html.php
@@ -217,7 +217,7 @@ formPanel
             $attributes
         )
     ),
-    formHidden('attribute', $struct->attribute),
+    formHidden('attribute', json_encode($struct->attribute)),
     formGroup
     (
         set::label($lang->api->desc),