//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);
}