The onerror
event handler of the
IDBTransaction
interface handles the error event, fired when a request
returns an error and bubbles up to the transaction object.
Note: Consider using IDBTransaction.onabort
instead
to handle non- successful completion of the transaction.
Note:
This feature is available in Web Workers.Syntax
transaction.onerror = function(event) { ... };
Example
In the following code snippet, we open a read/write transaction on our database and add
some data to an object store. Note also the functions attached to transaction event
handlers to report on the outcome of the transaction opening in the event of success or
failure. Note the transaction.onerror = function(event) { };
block, making
use of transaction.error
to help in reporting what went wrong when the
transaction was unsuccessful. For a full working example, see our To-do
Notifications app (view
example live.)
// Let us open our database
var DBOpenRequest = window.indexedDB.open("toDoList", 4);
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 below
db = DBOpenRequest.result;
// Run the addData() function to add the data to the database
addData();
};
function addData() {
// Create a new object ready for being inserted into the IDB
var newItem = [ { taskTitle: "Walk dog", hours: 19, minutes: 30, day: 24, month: "December", year: 2013, notified: "no" } ];
// open a read/write db transaction, ready for adding the data
var transaction = db.transaction(["toDoList"], "readwrite");
// report on the success of opening the transaction
transaction.oncomplete = function(event) {
note.innerHTML += '<li>Transaction completed: database modification finished.</li>';
};
transaction.onerror = function(event) {
note.innerHTML += '<li>Transaction not opened due to error: ' + transaction.error + '</li>';
};
// create an object store on the transaction
var objectStore = transaction.objectStore("toDoList");
// add our newItem object to the object store
var objectStoreRequest = objectStore.add(newItem[0]);
objectStoreRequest.onsuccess = function(event) {
// report the success of the request (this does not mean the item
// has been stored successfully in the DB - for that you need transaction.onsuccess)
note.innerHTML += '<li>Request successful.</li>';
};
};
Specifications
Specification | Status | Comment |
---|---|---|
Indexed Database API 2.0 The definition of 'onerror' in that specification. |
Recommendation | |
Indexed Database API 2.0 The definition of 'onerror' in that specification. |
Recommendation |
Browser compatibility
BCD tables only load in the browser
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.)
error
event