可以使用 cookie 来存储数据，它在用户的浏览器中保存了数据，但只能存储少量数据。如果需要存储大量数据，可以使用基于浏览器的数据库 IndexedDB。

示例代码：

// 使用 cookie 存储数据 document.cookie = "username=John Doe";

// 从 cookie 中读取数据 let username = document.cookie;

// 使用 IndexedDB 存储数据 let request = window.indexedDB.open("myDatabase", 1);

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

request.onsuccess = function(event) { let db = event.target.result; let transaction = db.transaction(["customers"], "readwrite"); let objectStore = transaction.objectStore("customers"); let request = objectStore.add({id: 1, name: "John Doe"});

request.onerror = function(event) { console.log("Error adding customer: " + event.target.errorCode); };

request.onsuccess = function(event) { console.log("Customer added."); }; };

// 从 IndexedDB 中读取数据 let request = window.indexedDB.open("myDatabase", 1);

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

request.onsuccess = function(event) { let db = event.target.result; let transaction = db.transaction(["customers"], "readonly"); let objectStore = transaction.objectStore("customers"); let request = objectStore.get(1);

request.onerror = function(event) { console.log("Error getting customer: " + event.target.errorCode); };

request.onsuccess = function(event) { console.log("Customer retrieved: " + event.target.result.name); }; };