IndexedDB 是一個用於儲存大量結構化資料的低階 API，通常在 Web 應用程式中用於客戶端儲存。以下是在 HTML5 中使用 IndexedDB 的基本步驟：

1. 開啟資料庫：

 javascript
 let db;
const request = window.indexedDB.open('YourDatabaseName', 1);

request.onerror = function (event) {
  console.log('Database error: ' + event.target.errorCode);
};

request.onsuccess = function (event) {
  db = event.target.result;
  console.log('Database opened successfully');
};

request.onupgradeneeded = function (event) {
  // This is called only if the database version is increased
  const db = event.target.result;
  const objectStore = db.createObjectStore('YourObjectName', { keyPath: 'id', autoIncrement: true });

  // You can define indexes here if needed
  objectStore.createIndex('indexName', 'propertyName', { unique: false });
};

2. 新增數據：

 javascript
 const transaction = db.transaction(['YourObjectName'], 'readwrite');
const objectStore = transaction.objectStore('YourObjectName');
const data = { id: 1, name: 'John Doe', age: 25 };

const request = objectStore.add(data);

request.onsuccess = function (event) {
  console.log('Data added successfully');
};

request.onerror = function (event) {
  console.log('Error adding data: ', event.target.error);
};

3. 檢索資料：

 javascript
 const transaction = db.transaction(['YourObjectName'], 'readonly');
const objectStore = transaction.objectStore('YourObjectName');
const request = objectStore.get(1); // Get data with ID 1

request.onsuccess = function (event) {
  const data = event.target.result;
  if (data) {
    console.log('Retrieved data:', data);
  } else {
    console.log('No data found with the specified ID');
  }
};

request.onerror = function (event) {
  console.log('Error retrieving data: ', event.target.error);
};

4.更新數據：

 javascript
 const transaction = db.transaction(['YourObjectName'], 'readwrite');
const objectStore = transaction.objectStore('YourObjectName');
const request = objectStore.put({ id: 1, name: 'Updated Name', age: 30 });

request.onsuccess = function (event) {
  console.log('Data updated successfully');
};

request.onerror = function (event) {
  console.log('Error updating data: ', event.target.error);
};

5. 刪除資料：

 javascript
 const transaction = db.transaction(['YourObjectName'], 'readwrite');
const objectStore = transaction.objectStore('YourObjectName');
const request = objectStore.delete(1); // Delete data with ID 1

request.onsuccess = function (event) {
  console.log('Data deleted successfully');
};

request.onerror = function (event) {
  console.log('Error deleting data: ', event.target.error);
};

這些範例涵蓋了 IndexedDB 中的基本 CRUD 操作。根據您的應用程序，您可能需要處理事務、建立多個物件儲存以及使用 IndexedDB 提供的更高級功能。