<?php
// powered by knuepower.de
$result = '';
if ($_SERVER['REQUEST_METHOD'] === 'POST') {
    $input = $_POST['input'] ?? '';
    $mode = $_POST['mode'] ?? 'encode';

    if ($mode === 'encode') {
        $result = base64_encode($input);
    } else {
        $result = base64_decode($input);
    }
}
?>
<form method="post">
    <textarea name="input" rows="3" cols="40" placeholder="Text eingeben" required><?= htmlspecialchars($_POST['input'] ?? '') ?></textarea><br>
    <label><input type="radio" name="mode" value="encode" checked> Kodieren</label>
    <label><input type="radio" name="mode" value="decode"> Dekodieren</label><br>
    <button type="submit">Ausführen</button>
</form>
<?php if ($result): ?>
<p><strong>Ergebnis:</strong><br><textarea rows="3" cols="40" readonly><?= htmlspecialchars($result) ?></textarea></p>
<?php endif; ?>
