如何从Firebase中的单个分支获取单个字符串，并将其放在HTML文本框中并对其进行更新？

<input type="text" id="myTextBox">

// 初始化Firebase
var config = {
  apiKey: "YOUR_API_KEY",
  authDomain: "YOUR_AUTH_DOMAIN",
  databaseURL: "YOUR_DATABASE_URL",
  projectId: "YOUR_PROJECT_ID",
  storageBucket: "YOUR_STORAGE_BUCKET",
  messagingSenderId: "YOUR_MESSAGING_SENDER_ID"
};
firebase.initializeApp(config);

// 获取数据库引用
var database = firebase.database();

// 获取分支数据
var branchRef = database.ref('branch');
branchRef.on('value', function(snapshot) {
  var data = snapshot.val();
  document.getElementById('myTextBox').value = data;
});

<script src="https://www.gstatic.com/firebasejs/8.10.0/firebase-app.js"></script>
<script src="https://www.gstatic.com/firebasejs/8.10.0/firebase-database.js"></script>
<script>
  // 上述JavaScript代码
  // ...
  // ...
  window.onload = function() {
    // 执行上述JavaScript代码
    // ...
    // ...
  };
</script>