Simple 3 PHP page (NO DATABASE) that user unchecks from 3 checkboxes and last page displays rest

******************************
page1.php( which is your login page)
**********************************
<?php
session_start();
 
  $username = $_POST['username'] ;
  $password = $_POST['password'] ;
  
include('function.php');
 
 if($_POST['submit'])
  {
  	if ($username == 'george' AND  $password =='112233')
	  {
	   session_register("username"); 
        $_SESSION['username'] = $_POST['username'] ; 
       
			
	         header('Location: page2.php');
	   }
	   
	  else 
	  {
	   echo "wrongpassword";
       }
  }
 
?>
 
<form action="<?php echo pf_script_with_get($SCRIPT_NAME); ?>" method="post">
 
<table>
<tr>
        <td>Username</td>
        <td><input type="text" name="username"></td>
</tr>
<tr>
        <td>Password</td>
        <td><input type="password" name="password"></td>
</tr>
<tr>
        <td></td>
        <td><input type="submit" name="submit" value="Login!"></td>
</tr>
</table>
</form>
 
*******************
page2.php - Your selection page
***************
<?php
session_start();
 
if(isset($_SESSION['username']) == FALSE) {        // Checking if username session is false, it will redirect to login page
	header('Location:  page1.php');
}
else { 
 
 
if($_POST['Spage2']){
$_SESSION['s1b1'] = $_POST['s1b1'];
$_SESSION['s1b2'] = $_POST['s1b2'];
$_SESSION['s1b3'] = $_POST['s1b3'];
 
header('location: page3.php');
exit;
}
?>
 
<form name="form1" method="post" action="<? $_SERVER['PHP_SELF']; ?>">
<?php
if(!empty($_SESSION['s1b1'])){
 ?>
<input type="checkbox" name="s1b1" id="checkbox" value="Book title 1" checked>
 
Book title 1 <br>
<?php
}
else
{
?>
 
<input type="checkbox" name="s1b1" id="checkbox" value="Book title 1" >
 
Book title 1 <br>
<?php
}
?>
 
 
<?php
if(!empty($_SESSION['s1b2'])){
 ?>
 
<input type="checkbox" name="s1b2" id="checkbox" value="Book title 2" checked >
 
Book title 2 <br>
<?php
}
else
{ 
?>
<input type="checkbox" name="s1b2" id="checkbox" value="Book title 2"  >
 
Book title 2 <br>
<?php
 
}
?>
 
 
<?php
if(!empty($_SESSION['s1b3'])){
 ?>
 
<input type="checkbox" name="s1b3" id="checkbox" value="Book title 3" checked >
 
Book title 3 <br>
<?php
}
else
{ 
?>
<input type="checkbox" name="s1b3" id="checkbox" value="Book title 3"  >
 
Book title 3 <br>
<?php
 
}
?>
 
 
<input name="Spage2" type="submit" value="Return Books">
 
</form>
<?php
}
?>
 
*****************
page3.php - Result
*****************
<?
session_start();
if(isset($_SESSION['username']) == FALSE) {        // Checking if username session is false, it will redirect to login page
	header('Location:  page1.php');
}
else { 
 
echo "Hi " ; echo  $_SESSION['username'] ;
echo "<br >";
echo"You have selected following books:";
echo "<br />"; 
if(!empty($_SESSION['s1b1'])){
 
echo $_SESSION['s1b1']."<br>";
$Vs1b1 = 1 ;
}
if(!empty($_SESSION['s1b2'])){
 
echo $_SESSION['s1b2']."<br>" ;
$Vs1b2 = 1;
}
if(!empty($_SESSION['s1b3'])){
 
echo $_SESSION['s1b3']."<br>" ;
$Vs1b3 = 1;
 
}
$vs = $Vs1b1+$Vs1b2+$Vs1b3;
 
echo "Total Books:" ;echo $vs ;echo" Books";
echo '<br />';
 
if(empty($_SESSION['s1b1'])){
 
echo" You still have this books to return:"; echo "Book Title1"; echo"<br>";
 
}
if(empty($_SESSION['s1b2'])){
 
echo" You still have this books to return:"; echo "Book Title2"; echo"<br>";
 
}
 
if(empty($_SESSION['s1b3'])){
 
echo" You still have this books to return:"; echo "Book Title3"; echo"<br>";
 
}
 
echo "<a href='page2.php'> goto Book Selecton page</a>";
echo"<br />";
echo "<a href='logout.php'> logout</a>";
}
?>
 
*****************
logout.php ' user logout and Reset checkbox
******************
<?php
session_start();
session_unregister("username");
// After logout if you want to start from beginning then uncomment these 3 lines it will reset all the session for checkbox
//session_unregister("s1b1");
//session_unregister("s1b2");
 
//session_unregister("s1b3");
 
 
header('Location:  page1.php');
?>
*************
function.php- userdefined
**************
<?php
function pf_script_with_get($script) {
	$page = $script;
	$page = $page . "?";
	
	foreach($_GET as $key => $val) {
		$page = $page . $key . "=" . $val . "&";  
	}
	
	//return substr($page, 0, strlen($page)-1);
}
?>