make a page called verify.php
then make another page with a form on it say verify.html and put a form on it with a drop down list with a month/day/year that they can put their birthdate in, make sure the dropdown with the year's name is "year" so the script can check
and in verify.php put this
PHP Code:
<?php
$year = $_POST['year'];
$age = date("Y") - $year;
if($age <= 18)
{
setcookie("ageverification", base64_encode($_SERVER['REMOTE_ADDR'] . "-" . time()), time() + (3600 * 24));
header("location: index.php");
exit;
}else{
header("location: verify.html");
exit;
}
?>
then on any page you want them to verify their age on, put this at the top of the page above EVERYTHING.
PHP Code:
<?php
if($_COOKIE['ageverification'] == false)
{
header("location: verify.html");
exit;
}
?>
i did this via the quick reply form, it may be buggy or whatever, its just a general idea and to help you figure out a solution