What are the disadvantages of using frames for the end user in PHP websites?

Using frames in PHP websites can lead to several disadvantages for the end user, including slower loading times, difficulty in bookmarking specific pages, and issues with search engine optimization. To solve this problem, it is recommended to use modern web development techniques such as CSS for layout and JavaScript for dynamic content loading.

<!DOCTYPE html>
<html>
<head>
    <title>Modern PHP Website</title>
    <link rel="stylesheet" type="text/css" href="styles.css">
</head>
<body>
    <header>
        <h1>Welcome to our website</h1>
    </header>
    <nav>
        <ul>
            <li><a href="index.php">Home</a></li>
            <li><a href="about.php">About Us</a></li>
            <li><a href="contact.php">Contact</a></li>
        </ul>
    </nav>
    <main>
        <p>This is the main content of the website.</p>
    </main>
    <footer>
        <p>© 2021 All rights reserved.</p>
    </footer>
</body>
</html>