Session

Primo form:

<div id="tabs-2">
                 <div id="register-form">
                    <h3><?php _e('Register for this site!','mdframework');?></h3>
                    <p><?php _e('Sign up now for the good stuff.','mdframework');?></p>
                    <!-- Let's set a cookie to store desidered username just in case we are using BuddyPress -->
                    <form id="registrazione" action="<?php echo site_url('wp-login.php?action=register', 'login_post') ?>" method="post">
                        <div class="username">
                            <label for="user_login"><?php _e('Username','mdframework'); ?>: </label>
                            <input type="text" name="user_login" value="Username" id="user_login" class="input" />
                        </div>
                        <div class="password">
                            <label for="user_email"><?php _e('Your Email','mdframework'); ?>: </label>
                            <input type="text" name="user_email" value="E-Mail" id="user_email" class="input"  />
                        </div>
                        <div class="login_fields">
                            <?php do_action('register_form'); ?>
                            <input type="submit" value="<?php _e('Sign up!','mdframework'); ?>" id="register" name="submit"/>
                            <input type="hidden" name="redirect_to" value="<?php echo $_SERVER['REQUEST_URI']; ?>?register=true" />
                        </div>
                </div>
            </form>
<?php

 /* starting the session */
 session_start();


 if (isset($_POST['submit'])) {
 $_SESSION['user_login'] = $_POST['user_login'];
 }
?>
            </div><!-- <div id="tabs-2"> -->








Secondo FORM:


<input type="text" name="signup_username" id="signup_username" value="<?php session_start(); if (isset($_SESSION['user_login'])){echo $_SESSION['user_login'];}else{ /* bp_signup_username_value()*/ echo 'Niente da dichiarare';};?>" />