XSS problem I need some help fixing...

[interpim]

OK... my bit of code is for paging in a guestbook script.  if anyone puts anything into the address bar besides a number it will display it aswell :/  anywho, does anyone know how to prevent this?

 

here is my code snippet.

 

$page = 1;
if(isset($_GET['page'])){
$page = $_GET['page'];
$x = $page*5-5;
}

[p2grace]

Try this:

 

$page = 1;
if(isset($_GET['page'])){
$page = $_GET['page'];
if(is_numeric($page)){
  $x = $page*5-5;
}
}