symfony1 ajax respones and add component on action

json response:

$this->getResponse()->setHttpHeader('Content-type', 'application/json');

return $this->renderText(json_encode($todo));

function addNewTodo(checklist_id)
{
  var body = jQuery('#todo_body_' + checklist_id).val();
    jQuery.ajax({
      url: "url_for('checklist/addtodo'); ?>",
      type: 'POST',
      data: {'id': checklist_id, 'body': body},
      dataType: 'json',
      beforeSend: function () {
        jQuery('#indicator').show();
      },
      success: function (data) {
        jQuery('#indicator').hide();
      }
    });
  return false;
}

---

component in action:

return $this->renderComponent ('checklist', 'checklist_tr', array(    'todo_id'  =>  $todo->getId(),    'todo_status'  =>  false,    'todo_body'  =>  $todo->getBody(),    'project_id' => $project_id));
function addNewTodo(checklist_id)
{
  var body = jQuery('#todo_body_' + checklist_id).val();
    jQuery.ajax({
      url: "url_for('checklist/addtodo'); ?>",
      type: 'POST',
      data: {'id': checklist_id, 'body': body},
      dataType: 'text',
      beforeSend: function () {
        jQuery('#indicator').show();
      },
      success: function (data) {
        jQuery('#indicator').hide();
      }
    });
  return false;
}