js 本地存储文件

// 存储数据
localStorage.setItem('username', 'JohnDoe');

// 读取数据
const username = localStorage.getItem('username');
console.log(username); // 输出: JohnDoe

// 删除数据
localStorage.removeItem('username');

// 清空所有数据
localStorage.clear();

let db;
const request = indexedDB.open('myDatabase', 1);

request.onupgradeneeded = function(event) {
  db = event.target.result;
  const objectStore = db.createObjectStore('users', { keyPath: 'id' });
  objectStore.createIndex('name', 'name', { unique: false });
};

request.onsuccess = function(event) {
  db = event.target.result;
};

request.onerror = function(event) {
  console.error('IndexedDB error:', event.target.errorCode);
};

// 添加数据
const transaction = db.transaction(['users'], 'readwrite');
const objectStore = transaction.objectStore('users');
const user = { id: 1, name: 'JohnDoe' };
objectStore.add(user);

// 读取数据
const getRequest = objectStore.get(1);
getRequest.onsuccess = function(event) {
  console.log(getRequest.result); // 输出: { id: 1, name: 'JohnDoe' }
};

<input type="file" id="fileInput" />
<img id="preview" src="" alt="File Preview" />

<script>
document.getElementById('fileInput').addEventListener('change', function(event) {
  const file = event.target.files[0];
  if (file) {
    const reader = new FileReader();
    reader.onload = function(e) {
      document.getElementById('preview').src = e.target.result;
    };
    reader.readAsDataURL(file);
  }
});
</script>