<!DOCTYPE html>
<html>
<head>
    <title>JavaScript Placement</title>
</head>
<body>
    <h1>JavaScript Placement</h1>
    <p id="output"></p>
    <script>
        // Initialize variables and manipulate DOM
        let message = "Hello, world!";
        document.getElementById("output").textContent = message;
    </script>
</body>
</html>