多步表单如何使用不同页面之间的信息

I try to use a multi set form in php because I don't know jquery and javascript (and difficulties to understand it).

First here what I would like to do:

Page 1:

Q1 How many number you want? User for example enter "2"

Page 2:

Q2 How many letter for each number you want:

(looks like : number 1: --- number 2: ----)

user for example enter "2" for the 1st one and "1" for the 2nd one.

Page 3:

(looks like:)

number 1: letter 1:--- letter 2:----

number 2: letter 1: ---

So far everything works well between page 1 and 2, but nothing happen between page 2 and 3 The other problem also is if the user go "back" between 3 and 2, the page 2 have nothing because the value of the first page is "lost"

I'm searching for a long time and don't find anything, if you have any suggestions I will be happy.

Here is my code:

   <?php
   if ( isset( $_POST["step"] ) and $_POST["step"] >= 1 and $_POST["step"]<= 4 ) {
call_user_func( "processStep" . (int)$_POST["step"] );
   } else {
displayStep1();
    }
    function processStep1() {
displayStep2();
    }
   function processStep2() {
if ( isset( $_POST["submitButton"] ) and $_POST["submitButton"] =="< Back" ) {
    displayStep1();
} else {
    displayStep3();
}
    }
   function processStep3() {
if ( isset( $_POST["submitButton"] ) and $_POST["submitButton"] =="< Back" ) {
    displayStep2();
} else {
    displayThanks();
}
     }
    function displayStep1() {
    ?>
<h1>Step 1</h1>

<form action="" method="post">

<input type="hidden" name="step" value="1" />
<input type="hidden" name="number2" value="" />

<label for="number">Combien de chiffres?</label>
<input type="text" name="number" id="number" value=" " />

<div style="clear: both;">
<input type="submit" name="submitButton" id="nextButton" value="Next" />

</form>

<?php
}
function displayStep2() {
?>

<h1>Step 2</h1>
<form action="" method="post">

<input type="hidden" name="step" value="2" />
<input type="hidden" name="number" value="" />
<label for="number2">Combien de lettre pour chaque chiffres?</label>

<?php 
$num = $_POST['number'];
    for ($i = 1; $i <= $num; $i++) {
        echo "Numero ";
        echo $i;
?>  

<input type="text" name="number2" id="number2"/>

<?php
}
?>

<div style="clear: both;">
<input type="submit" name="submitButton" id="nextButton" value="Next &gt;" />
<input type="submit" name="submitButton" id="backButton" value="&lt; Back" />
</form>

<?php
}
function displayStep3() {
?>

<h1>Step 3</h1>
<form action="" method="post">

<input type="hidden" name="step" value="3" />
<input type="hidden" name="number" value="" />
<input type="hidden" name="number2" value="" />
<label for="number3">Choisir lettres</label>

<?php 
$num = $_POST['number'];
    for ($i = 1; $i <= $num; $i++) {
        echo "Numero ";
        echo $i;

    $num2 = $_POST['number2'];
        for ($j = 1; $j <= $num2; $j++) {
            echo "Lettre ";
            echo $j;
?>  

<input type="text" name="number3" id="number3"/>

<?php
}
}
?>

<div style="clear: both;">
<input type="submit" name="submitButton" id="nextButton" value="Next &gt;" />
<input type="submit" name="submitButton" id="backButton" value="&lt; Back" />
</form>

<?php
}
function displayThanks() {
?>

<h1>Merci</h1>

<?php
}
?>