ERROR:
Warning: Cannot modify header information - headers already sent by (output started at /storage/ssd4/241/3939241/public_html/post.php:4) in /storage/ssd4/241/3939241/public_html/post.php on line 9

CODE:
<?php
$user = $_POST['nm'];
$password = $_POST['pw'];
echo $user;
echo $password;

if ($user == 'username') {
    if ($password == 'password'){
        header ('Location: home.html');
    }
    else{
        echo 'Wrong!';
    }
}
else{
    echo 'Wrong!';
}

?>