Form variable forward question

[JinF]

I am creating a webform that has 3 parts spread over 3 pages. The idea is to save all variables on the form as the user goes along, then page 3 sends all the variables from all pages to a script to enter them into a database.
I am using

<input type="submit" value="Continue to part 2" name="part2">

to forward the variables from the first to the second page and it works fine, also use the same code to forward the variables from page 2 to page 3. The problem is that the variables of page 1 do not reach page 3 this way. What do I need to do to be able to transfer the variables from page 1 all the way through page 3 to a submit script?

[Houdini]

You need to use session variables so as you pass these variables after page 1 to page 2 you will need to use $SESSION array variables to save these variables. for example on page 2 start the page with a session_start(); then assign the $POST or $GET variables to $SESSION variables e.g. page2.php

<?php
session_start();
$_SESSION['username'] = $_POST['username'];
$_SESSION['address'] = $_POST['address'];
...
?>