Recommended method to capture GET parameters?

[lsb57]

All,

What's the best way to capture a GET parameter passed when the main page is invoked similarly to http://site.here/index.php?main_page=index&a_parameter=some_value

One way is to add a section to application_top.php, like this:

if ( isset($_GET["a_parameter"]) )
{
$_SESSION["a_parameter"] = $_GET["a_parameter"];
setcookie("a_parameter", $_GET["a_parameter"], time() + 60*60*24*3, "/");

}

While this works, it makes upgrades more complicated. Is there a better way, maybe in the form of attaching to a notification message? If I can keep the code outside of the standard application_top.php, upgrade would be simpler.

Thanks!