Ok.. probemoslo de esta forma..
Código PHP:
<?php
$nivel = $_REQUEST["niv"];
echo "<a href='javascript:void(0)' onclick='send()'>Probar</a><br>";
if (!isset($_REQUEST["niv"]))
echo'<script type="text/javascript">function send(){location.replace("GETvariables.php?niv=nivel");}</script>';
else {
echo "<pre>";
print_r($_REQUEST);
echo "</pre>";
}
?>