Formulaire PHP - Plusieurs étapes

<form action="page2.php" method="POST">
<input type="text" name="data1" />
<input type="submit" value="Suivant" />
</form>

if(isset($_POST['data1'])) {
$arr = array();
$arr['data1'] = $_POST['data1'];
}
echo "<form action='page3.php' method='POST'>
<input type='text' name='data2' />"; 
foreach($arr as $k => $v) {
echo "<input type='hidden' name='$k' value='$v' />";
}
echo "<input type='submit' value='Suivant' />
</form>";

if(isset($_POST['data2'])) {
$arr = array();
foreach($_POST as $k=>$v) {
$arr[$k] = $v;
}
}
echo "<form action='page4.php' method='POST'>
<input type='text' name='data3' />"; 
foreach($arr as $k => $v) {
echo "<input type='hidden' name='$k' value='$v' />";
}
echo "<input type='submit' value='Suivant' />
</form>";