The onblocked
event handler of the IDBOpenDBRequest
interface is the event handler for the blocked
event. This event is triggered when the upgradeneeded
should be triggered because of a version change but the database is still in use (that is, not closed) somewhere, even after the versionchange
event was sent.
Note: This feature is available in Web Workers.
Syntax
IDBOpenDBRequest.onblocked = function(event) { ... };
Example
var db;
// Let us open our database
var request = indexedDB.open("toDoList", 4);
// these two event handlers act on the database being opened
// successfully, or not
request.onerror = function(event) {
note.innerHTML += '<li>Error loading database.</li>';
};
request.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 below
db = request.result;
// Run the displayData() function to populate the task list with
// all the to-do list data already in the IDB
displayData();
};
// This event handles the event whereby a new version of the
// database needs to be created. Either one has not been created
// before, or a new version number has been submitted via the
// window.indexedDB.open line above
//it is only implemented in recent browsers
request.onupgradeneeded = function(event) {
var db = event.target.result;
db.onerror = function(event) {
note.innerHTML += '<li>Error loading database.</li>';
};
// Create an objectStore for this database
var objectStore = db.createObjectStore("toDoList", { keyPath: "taskTitle" });
...
};
request.onblocked = function() {
console.log("Your database version can't be upgraded because the app is open somewhere else.");
}
Specifications
Specification | Status | Comment |
Indexed Database API 2.0The definition of 'onblocked' in that specification. | Recommendation | |
Indexed Database API DraftThe definition of 'onblocked' in that specification. | Recommendation |
Browser compatibility
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.
Update compatibility data on GitHub
Desktop | Mobile | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
onblocked
|
Chrome Full support 24 Full support 24 No support 23 — 57 Prefixed' Implemented with the vendor prefix: webkit |
Edge
Full support 12 |
Firefox Full support 16 Full support 16 No support 10 — 16 Prefixed' Implemented with the vendor prefix: moz |
IE
Partial support 10 |
Opera
Full support 15 |
Safari
Full support 7 |
WebView Android Full support Yes Full support Yes No support ? — 57 Prefixed' Implemented with the vendor prefix: webkit |
Chrome Android Full support 25 Full support 25 No support 25 — 57 Prefixed' Implemented with the vendor prefix: webkit |
Firefox Android
Full support 22 |
Opera Android
Full support 14 |
Safari iOS
Full support 8 |
Samsung Internet Android Full support 1.5 Full support 1.5 No support 1.5 — 7.0 Prefixed' Implemented with the vendor prefix: webkit |
Legend
- Full support
- Full support
- Partial support
- Partial support
- Requires a vendor prefix or different name for use.'
- Requires a vendor prefix or different name for use.
See also
- Using IndexedDB
- Starting transactions:
IDBDatabase
- Using transactions:
IDBTransaction
- Setting a range of keys:
IDBKeyRange
- Retrieving and making changes to your data:
IDBObjectStore
- Using cursors:
IDBCursor
- Reference example: To-do Notifications ([[../../../../../../../mdn.github.io/to-do-notifications/index|view example live]].)
blocked
event
IDBOpenDBRequest.onblocked by Mozilla Contributors is licensed under CC-BY-SA 2.5.