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IDBFactory

Baseline Widely available *

This feature is well established and works across many devices and browser versions. It’s been available across browsers since ⁨2015年7月⁩.

* Some parts of this feature may have varying levels of support.

IndexedDB API 的IDBFactory 接口让程序可以异步存取 indexed databases。window.indexedDB 对象实现了这个接口。你可以通过这个对象而不是直接使用IDBFactory接口打开——创建或者连接——和删除一个数据库。

Methods

IDBFactory.open: 请求打开一个数据库的连接(connection to a database)。
IDBFactory.deleteDatabase: 请求删除数据库。
IDBFactory.cmp: 比较两个键的方法并返回一个结果,表明哪个值更大。

过时的 Methods

IDBFactory.open, the original version 已弃用: 一个被废弃的方法请求打开一个数据库的连接,仍然在一些浏览器中被实施 (connection to a database).

In the following code snippet, we make a request to open a database, and include handlers for the success and error cases. For a full working example, see our To-do Notifications app (view example live.)

var note = document.querySelector("ul");
// In the following line, you should include the prefixes of implementations you want to test.
window.indexedDB =
 window.indexedDB ||
 window.mozIndexedDB ||
 window.webkitIndexedDB ||
 window.msIndexedDB;
// DON'T use "var indexedDB = ..." if you're not in a function.
// Moreover, you may need references to some window.IDB* objects:
window.IDBTransaction =
 window.IDBTransaction ||
 window.webkitIDBTransaction ||
 window.msIDBTransaction;
window.IDBKeyRange =
 window.IDBKeyRange || window.webkitIDBKeyRange || window.msIDBKeyRange;
// (Mozilla has never prefixed these objects, so we don't need window.mozIDB*)
// Let us open version 4 of our database
var DBOpenRequest = window.indexedDB.open("toDoList", 4);
// these two event handlers act on the database being opened successfully, or not
DBOpenRequest.onerror = function (event) {
 note.innerHTML += "<li>Error loading database.</li>";
};
DBOpenRequest.onsuccess = function (event) {
 note.innerHTML += "<li>Database initialised.</li>";
 // store the result of opening the database in the db variable. This is used a lot later on, for opening transactions and suchlike.
 db = request.result;
};