<?php if(isset($_POST['mail']) && $_POST['mail ... ... <看更多>

3 return call_user_func_array(array(&$controller, $method), empty($params) ? null : $params);. 4 $plugin = empty($this->request['plugin ... ... <看更多>

If you have a form with a "username" field and user submits it without filling it, an empty string gets sent to the server and therefore $_POST["username"] ... ... <看更多>