<?php
session_start();
$limit = 1; // thoi gian (s) han che giua hai lan truy cap
$delay = 2; // thoi gian (s) phai cho de load trang
$last = ($_SESSION['time'] == NULL) ? 0 : $_SESSION['time'];
$_SESSION['time'] = time();
if ( $limit >= (time() - $last) ) {
echo ' <html>...