$msg = "";

    \My PHP code that will execute in before proceeding the change password site


        if(isset($_POST['submitBtnLogin'])) {
$answer = trim($_POST['ans']);
$username = ($_SESSION['username']);
if($answer != "") {
    try {
        $query = "select * from `tbl_user` where username = :username and
        `answer`=:answer";
       $stmt = $db->prepare($query);
        $stmt->bindParam('answer', $answer, PDO::PARAM_STR);
        $stmt->bindParam('username', $username, PDO::PARAM_STR);
        $stmt->execute();
        $count = $stmt->rowCount();
        $row   = $stmt->fetch(PDO::FETCH_ASSOC);
        if($count == 1 && !empty($row)) {
            $_SESSION['fid']  = $row['id'];
            header('location:changepass.php');
        } else {
            echo "<script>alert('Incorrect Answer');</script>";

        }
    } catch (PDOException $e) {
        echo "Error : ".$e->getMessage();
    }
} else {
    $msg = "Both fields are required!";
}