IDBOpenDBRequest: blocked event

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范例
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blocked handler is executed when an open connection to a database is blocking a versionchange transaction on the same database.

冒泡	No
可取消	No
接口	`IDBVersionChangeEvent`
事件处理程序特性	`onblocked`

范例

使用 addEventListener() :

// Open the database
const DBOpenRequest = window.indexedDB.open('toDoList', 4);
DBOpenRequest.onupgradeneeded = (event) => {
  const db = event.target.result;
  db.onerror = () => {
    console.log('Error creating database');
  };
  // Create an objectStore for this database
  var objectStore = db.createObjectStore('toDoList', { keyPath: 'taskTitle' });
  // define what data items the objectStore will contain
  objectStore.createIndex('hours', 'hours', { unique: false });
  objectStore.createIndex('minutes', 'minutes', { unique: false });
  objectStore.createIndex('day', 'day', { unique: false });
  objectStore.createIndex('month', 'month', { unique: false });
  objectStore.createIndex('year', 'year', { unique: false });
};
DBOpenRequest.onsuccess = (event) => {
  // Let's try to open the same database with a higher revision version
  const req2 = indexedDB.open('toDoList', 5);
  // In this case the onblocked handler will be executed
  req2.addEventListener('blocked', () => {
    console.log('Request was blocked');
  });
};

使用 onblocked 特性：

// Open the database
const DBOpenRequest = window.indexedDB.open('toDoList', 4);
DBOpenRequest.onupgradeneeded = (event) => {
  const db = event.target.result;
  db.onerror = () => {
    console.log('Error creating database');
  };
  // Create an objectStore for this database
  var objectStore = db.createObjectStore('toDoList', { keyPath: 'taskTitle' });
  // define what data items the objectStore will contain
  objectStore.createIndex('hours', 'hours', { unique: false });
  objectStore.createIndex('minutes', 'minutes', { unique: false });
  objectStore.createIndex('day', 'day', { unique: false });
  objectStore.createIndex('month', 'month', { unique: false });
  objectStore.createIndex('year', 'year', { unique: false });
};
DBOpenRequest.onsuccess = (event) => {
  // Let's try to open the same database with a higher revision version
  const req2 = indexedDB.open('toDoList', 5);
  // In this case the onblocked handler will be executed
  req2.onblocked = () => {
    console.log('Request was blocked');
  };
};

浏览器兼容性

The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request. 更新 GitHub 上的兼容性数据

	桌面						移动
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
`blocked` event	Chrome 24 24 不支持 23 — 57 Prefixed Prefixed Implemented with the vendor prefix: webkit	Edge 12	Firefox 16 16 不支持 10 — 16 Prefixed Prefixed Implemented with the vendor prefix: moz	IE 部分支持 10	Opera 15	Safari 7	WebView Android Yes Yes 不支持 ? — 57 Prefixed Prefixed Implemented with the vendor prefix: webkit	Chrome Android 25 25 不支持 25 — 57 Prefixed Prefixed Implemented with the vendor prefix: webkit	Firefox Android 22	Opera Android 14	Safari iOS 8	Samsung Internet Android 1.5 1.5 不支持 1.5 — 7.0 Prefixed Prefixed Implemented with the vendor prefix: webkit

图例

完整支持
部分支持
要求使用供应商前缀或不同名称。

另请参阅

使用 IndexedDB
onblocked event handler property

元数据

最后修改： Mar 18, 2019

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范例

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图例

另请参阅

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