Full error: Warning: Cannot modify header information - headers already sent by (output started at /storage/ssd2/431/18637431/public_html/mysql.php:1) in /storage/ssd2/431/18637431/public_html/login.php on line 26 I builded an login system with php and I want to save the user that is logged in, in a php cookie called name but i get this error . why?
enter code here
<?php
$correct = false;
if(isset($_POST["submit"])){
require("mysql.php");
$stmt = $mysql->prepare("SELECT * FROM accounts WHERE USERNAME = :user"); //Username überprüfen
$stmt->bindParam(":user", $_POST["username"]);
$stmt->execute();
$count = $stmt->rowCount();
if($count == 1){
//Username ist frei
$row = $stmt->fetch();
if(password_verify($_POST["pw"], $row["PASSWORD"])){
$correct = true;
$userna = $row["USERNAME"];
// session_start();
// $_SESSION["username"] = $row["USERNAME"];
// header("Location: index.html");
} else {
echo "Der Login ist fehlgeschlagen";
}
} else {
echo "Der Login ist fehlgeschlagen";
}
if($correct ==true){
setcookie("name","$userna");
echo("Anmeldung war erfolgreich. ");
//echo("Hallo " + $userna);
//setcookie("name","$userna");
}
}
?>
<!DOCTYPE html>
<html lang="en" dir="ltr">
<head>
<meta charset="utf-8">
<title>Login</title>
</head>
<body>
<h1>Anmelden</h1>
<form action="login.php" method="post">
<input type="text" name="username" placeholder="Username" required><br>
<input type="password" name="pw" placeholder="Passwort" required><br>
<button type="submit" name="submit">Einloggen</button>
</form>
<br>
<a href="register.php">Noch keinen Account?</a>
<script>
var name = "<?= $userna ?>";
document.cookie = "user=" + name;
// mycookie = document.cookie;
alert("Hallo "+ name + " du wurdest erfolgreich eingeloggt" );
</script>
</body>
