I'm not entirely sure what you want but think you want to get access to the changed values.
For a start, when you submit the data it helps for the same page to handle it. So just go to your openening <form> tag and change the value for action to the current page.
<form action="<?php print $_SERVER['php_self']; ?>" method="post" type="submit">
Upon pressing submit, the current page will have access to the submitted data. So if your page looked something like this before:
<?php
$pt = 'Page Title';
require_once ('./header.php');
?>
This is where the site content goes. All your rows of data, etc. would be here.
<input type="checkbox" name="checkbox1" value="Checkbox 1" />
<form action="<?php print $_SERVER['php_self']; ?>" method="post" type="submit">
<input type="submit" name="submit" value="Update">
</form>
<?php
require_once ('./footer.php');
?>
You will need something to get the data and manipulate it. This is easily done by doing whatever you want to it before the actual page is shown. Like so:
<?php
if (isset($_POST['submit'])) {
// Submit button has been pressed.
// Easier to refer to
$cb1 = $_POST['checkbox1']
//You can then do anything you want with $cb1
}
$pt = 'Page Title';
require_once ('./header.php');
?>
This is where the site content goes. All your rows of data, etc. would be here.
<input type="checkbox" name="checkbox1" value="Checkbox 1" />
<form action="<?php print $_SERVER['php_self']; ?>" method="post" type="submit">
<input type="submit" name="submit" value="Update">
</form>
<?php
require_once ('./footer.php');
?>
I hope this is what you meant.