Pega Title (html e php)

<form method="POST" action="">
    <label for="url-input">Insira uma URL:</label>
    <input type="text" id="url-input" name="url">
    <button type="submit" name="submit">Obter título</button>
</form>

<p id="title">
    <?php
        if (isset($_POST['submit'])) {
            $url = $_POST['url'];
            $html = file_get_contents($url);
            $title = preg_match('/<title>(.*)<\/title>/', $html, $matches);
            echo $matches[1];
        }
    ?>
</p>