库（IndexedDB）是一种可在网页浏览器中存储和检索大量结构化数据的浏览器内数据库，它使用键值对存储数据。您可以通过以下步骤在HTML中使用IndexedDB：
let db;
const request = indexedDB.open('myDatabase', 1);
request.onerror = function(event) {
console.log('Database error: ' + event.target.errorCode);
};
request.onsuccess = function(event) {
db = event.target.result;
};const objectStore = db.createObjectStore('myObjectStore', { keyPath: 'id' });
objectStore.createIndex('name', 'name', { unique: false });const transaction = db.transaction(['myObjectStore'], 'readwrite');
const objectStore = transaction.objectStore('myObjectStore');
const data = { id: 1, name: 'John Doe', email: 'johndoe@email.com'};
const request = objectStore.add(data);
request.onsuccess = function(event) {
console.log('Data added successfully');
};const transaction = db.transaction(['myObjectStore'], 'readonly');
const objectStore = transaction.objectStore('myObjectStore');
const index = objectStore.index('name');
const request = index.get('John Doe');
request.onsuccess = function(event) {
console.log(request.result);
};总之，IndexedDB使得在浏览器中使用数据库变得容易且方便。它提供了一种可靠的方式来存储和检索大量结构化数据，并且对于那些需要离线访问他们的网络应用程序而言非常有用。