//限制频繁提交
$feedback_session = isset($_COOKIE["feedback_session"]) ? $_COOKIE["feedback_session"] : 0;
if($feedback_session != '') {
    if (2-$feedback_session==1){
        $this->error("Sorry, you can't submit frequently within one minute！", '', 3);
    }
}else{
    $expire = time() + 60;
    setcookie("feedback_session", 1, $expire);
}