Retaining checkbox status of a form after submitting it

we will learn here how to post back or retain the value ( status ) of the checkbox.
We will use php header redirection to post back the values to our main page where checkbox is present. We will call form page as first page and action or submitted page as second page.

The form data will be received by second page and it is supposed to post back the form data back to form page by using query string through address bar. To keep the second page simple we will keep only the redirection part. Here we have excluded the part which takes care if the form passes its validation and execute the actual script (redirection part).

Here is the code of our form with two checkboxes, pb-check.php

<?php
$t1=$_GET['t1'];
$t2=$_GET['t2'];

if($t1=="yes"){$t1v="checked";}
else{$t1v=="";}

if($t2=="yes"){$t2v="checked";}
else{$t2v=="";}
?>

HTML Form code:

<form method="post" action="pb-chk.php">
<input type="checkbox" name="t1" value="yes" $t1v /> This is first checkbox <br />
<input type="checkbox" name="t2" value="yes" $t2v /> This is second checkbox
<input type="submit" value="Submit">
</form>

Here is the code of second page, pb-chk.php

<?php
$t1=$_POST['t1'];
$t2=$_POST['t2'];

header ("Location: pb-check.php?t1=$t1&t2=$t2");
?>