Getting variable from url

How can I get a variable from a self url?

http://www.test.net/test.php?a=112/testing

I just want to beable to grab

a=112/testing

 

Use:

echo $_SERVER['QUERY_STRING'];

PHP:

to grab that part.

 

<?
echo $_GET['a'];
?>

 

thanks guys!

 

just curious how can I get this if it was a external url?

 

$external_url = "http://www.test.net/test.php?a=112/testing";
echo substr(strrchr($external_url, '?'),1);

PHP: