Form Submit to change/modify session variables in PHP - php

Question

At the top I have a session start and the session ID can be passed across all the webpages because the ID is the same on all, this also includes a session variable called 'username' with the value of Guest.
I want to change this variable to the one entered in the form.
This is my first post so sorry for any mistakes.
<form class="form1" method="post" action="./" id="form1">
<fieldset>
<ul>
<p>Please enter your username to continue to the webshop.</p>
<label for="name">User Name:</label><span><input type="text" name="username" placeholder="User Name" class="required" role="input" aria-required="true"/></span>
<input class="submit .transparentButton" value="Next" type="submit" name="Submit"/>
</ul>
<br/>
</fieldset>
</form>
<?
if (isset($_POST['Submit'])) {
$_SESSION['username'] = $_POST['username'];
}
?>
Thanks

Answer 1

You need to take out ./ is in the action="" quotes like below (this is because you are using the same file to process the form)... and always start your php opening with <?php
<form class="form1" method="post" action="" id="form1">
<fieldset>
<ul>
<p>Please enter your username to continue to the webshop.</p>
<label for="name">User Name:</label><span><input type="text" name="username" placeholder="User Name" class="required" role="input" aria-required="true"/></span>
<input class="submit .transparentButton" value="Next" type="submit" name="Submit"/>
</ul>
<br/>
</fieldset>
</form>
<?php
if (isset($_POST['Submit'])) {
$_SESSION['username'] = $_POST['username'];
}
?>
And if you want to test it try something like this:
<?php
if (isset($_POST['Submit'])) {
$_SESSION['username'] = $_POST['username'];
// Use the following code to print out the variables.
echo 'Session: '.$_SESSION['username'];
echo '<br>';
echo 'POST: '.$_POST['username'];
}
?>
Tested the code after making the changes, and it works fine... look:
Update answer based of requests in the comments
<form class="form1" method="post" action="./" id="form1">
<fieldset>
<ul>
<p>Please enter your username to continue to the webshop.</p>
<label for="name">User Name:</label><span><input type="text" name="username" placeholder="User Name" class="required" role="input" aria-required="true"/></span>
<input class="submit .transparentButton" value="Next" type="submit" name="Submit"/>
</ul>
<br/>
</fieldset>
</form>
PUT THIS IN YOUR index.php
<?php
if (isset($_POST['Submit'])) {
$_SESSION['username'] = $_POST['username'];
// Use the following code to print out the variables.
echo 'Session: '.$_SESSION['username'];
echo '<br>';
echo 'POST: '.$_POST['username'];
}
?>