iframe et url

<script>
function url1(v1){ 
alert(v1);
window.open('page1.php?val1='+v1); 
}
</script>
<a href="" onclick="url1('aaafffff');">test</a>

<?php
if(isset($_GET['val1'])){
echo $_GET['val1'];
echo '<br><iframe src="page2.php?val1='.$_GET['val1'].'"></iframe>';
}
?>

<?php
if(isset($_GET['val1'])){
echo $_GET['val1'];
}
?>