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 2.0 The definition of 'onblocked' in that specification. |
Recommendation | |
Indexed Database API Draft The 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.
Desktop | Mobile | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
onblocked | Chrome
Full support
24
| Edge Full support 12 | Firefox
Full support
16
| IE Partial support 10 | Opera Full support 15 | Safari Full support 7 | WebView Android
Full support
Yes
| Chrome Android
Full support
25
| Firefox Android Full support 22 | Opera Android Full support 14 | Safari iOS Full support 8 | Samsung Internet Android
Full support
1.5
|
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 (view example live.)
blocked
event