Fix javascript error (cannot join null)

diff --git a/templates/CRM/Event/Form/Participant.tpl b/templates/CRM/Event/Form/Participant.tpl
index dbba237f4ed5be70f4b7fb6ccab4e60e5c99ea4a..c37ce5f6583b89a44ae34710bfc6f937283581ff 100644 (file)
--- a/templates/CRM/Event/Form/Participant.tpl
+++ b/templates/CRM/Event/Form/Participant.tpl
@@ -374,8 +374,8 @@
         });
 
         function buildRoleCustomData() {
-          var roleId = $('select[name^=role_id]', $form).val().join();
-          CRM.buildCustomData('Participant', roleId, {/literal}{$roleCustomDataTypeID}{literal});
+          var roleId = $('select[name^=role_id]', $form).val() || [];
+          CRM.buildCustomData('Participant', roleId.join(), {/literal}{$roleCustomDataTypeID}{literal});
         }
 
         //build fee block