unexpected token export firebase-app.js:1590

I am trying firebase web for first time, i was following the documentation still code isn't working and giving this "unexpected token 'export' " error in console. code:

<!DOCTYPE html>
<html>
<head>
    <title> Firebase Demo </title>
    <script src="https://www.gstatic.com/firebasejs/9.0.2/firebase-app.js"/>
    <script src="https://www.gstatic.com/firebasejs/9.0.2/firebase-auth.js"/>
    <script src="https://www.gstatic.com/firebasejs/9.0.2/firebase-database.js"/>
    <script>
        const firebaseConfig = {
          #firebase config info
        };

        // Initialize Firebase
        const app = firebase.initializeApp(firebaseConfig);

        const database = firebase.database();
        database.ref("List/"+"Targets").set({
            name:"niel",
            state:"alive"
        });
    </script>
</head>
<body>
<h1 align="center">Firebase Jinx</h1>
</body>
</html>

please help, thank you