Thank sourjya
Had tried with “return json_encode($ now);” but also caused error.
In the end it was like that and it works correctly.
test/src/Controller/AjaxController.php
public function simpleAction()
{
if ($this->request->is(array('ajax')))
{
$now = new Time();
// the order of these three lines is very important !!!
$resultJ = json_encode(array('result' => array('now' => $now)));
$this->response->type('json');
$this->response->body($resultJ);
return $this->response;
}
}