PHP change post target when user logs in successfully - php

Question

Here is my form that is using login.php to check if the user is registered, etc.
<form action="login.php" method="post" target="SHOW">
<ul id="login">
<li>
Username:<br />
<input type="text" name="username">
</li>
<li>
Password:<br />
<input type="password" name="password">
</li>
<li>
Submit:
<br />
<input type="submit" name="log in">
</li>
<li>
Register</li>
</ul>
</form>
<iframe id="iframe" name="SHOW" scrolling="no"></iframe>
My dilemma stems with the iframe tags I'm using to display the error messages. If the user is registered I would like to redirect him back to index.php as you can see at the end of the PHP ---> header('Location: index.php');
Problem is that iframe doesn't allow for redirecting. So, I would like to change the target from ---> target="SHOW" to target="_top" or something like that. So, the user is redirected after successfully logging in without using any JavaScript.
My failed attempt at accomplishing this --> $href->removeAttribute('target');
$href->setAttribute("target", "_top");
Here is login.php.
<?php
include 'core/init.php';
if(empty($_POST) === false){
$username = $_POST['username'];
$password = $_POST['password'];
if(empty($username) || empty($password) === true){
$errors[] = 'You need to enter a username and password';
} else if (user_exists($username) === false){
$errors[] = 'We can\'t find that username. Have you registered?';
} else if (user_active($username) === false){
$errors[] = 'You haven\'t activated your account!';
} else {
$login = login($username, $password);
if($login === false){
$errors[] = 'That username/password combination is incorrect';
} else {
$_SESSION['user_id'] = $login;
$href->removeAttribute('target');
$href->setAttribute("target", "_top");
header('Location: index.php');
exit();
}
}
print_r($errors);
}
?>

Answer 1

Since you're POST-ing to the iframe, any action taken by the response will only be valid for the context of the iframe itself, which means that doing a regular HTTP redirection will only change the content of the iframe.
If you want to keep the iframe (which I'd advice against, and instead keep both the error handling and logging in the same controller / file that displays the form), you can redirect by using javascript in your iframe response:
<script type="text/javascript">
parent.location.href = 'http://www.bbc.co.uk/';
</script>
Not pretty, but it works.