代码一

<?php
session_start();
$allow_sep = "60";
if (isset($_SESSION["post_sep"])){
if (time() - $_SESSION["post_sep"] < $allow_sep)
{exit("孩子你能消停一下么？刷新请60秒后继续！");}
else{$_SESSION["post_sep"] = time();}
}else{$_SESSION["post_sep"] = time();}
?>

代码二

<?php
//代理IP直接退出
empty($_SERVER['HTTP_VIA']) or exit('Access Denied');
//防止快速刷新，在设置的时间内到达设置次数就跳转的设定的页面
session_start();
$seconds = '3'; //时间段[秒]
$refresh = '3'; //刷新次数
//设置监控变量
$cur_time = time();
if(isset($_SESSION['last_time'])){
    $_SESSION['refresh_times'] += 1;
}else{
    $_SESSION['refresh_times'] = 1;
    $_SESSION['last_time'] = $cur_time;
}
//处理监控结果
if($cur_time - $_SESSION['last_time'] < $seconds){
    if($_SESSION['refresh_times'] >= $refresh){
        //跳转至攻击者服务器地址
        header(sprintf('Location:%s', 'http://127.0.0.1'));
        exit('Access Denied');
    }
}else{
    $_SESSION['refresh_times'] = 0;
    $_SESSION['last_time'] = $cur_time;
}
?>

代码三 js防止F5频繁刷新代码

<script>
document.onkeydown = function(e){
e = window.event || e;
var keycode = e.keyCode || e.which;
if( keycode = 116){
if(window.event){// ie
try{e.keyCode = 0;}catch(e){}
e.returnValue = false;
}else{e.preventDefault();}
}}
</script>