IDBOpenDBRequest: blocked event
The blocked
handler is executed when an open connection to a database is blocking a versionchange
transaction on the same database.
This event is not cancelable and does not bubble.
Syntax
Use the event name in methods like addEventListener()
, or set an event handler property.
addEventListener('blocked', event => { });
onblocked = event => { };
Event type
An IDBVersionChangeEvent
. Inherits from Event
.
Event properties
Also inherits properties from its parent, Event
interface.
IDBVersionChangeEvent.oldVersion
Read only-
Returns the old version of the database.
IDBVersionChangeEvent.newVersion
Read only-
Returns the new version of the database.
Examples
Using 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');
});
};
Using the onblocked
property:
// 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');
};
};
Browser compatibility
BCD tables only load in the browser