Note: This feature is available in Web Workers.

The IDBOpenDBRequest interface of the IndexedDB API provides access to the results of requests to open or delete databases (performed using and IDBFactory.deleteDatabase), using specific event handler attributes.

EventTarget IDBRequest IDBOpenDBRequest

Instance properties

Also inherits properties from its parents IDBRequest and EventTarget.

Instance methods

No methods, but inherits methods from its parents IDBRequest and EventTarget.


Events defined on parent interfaces, IDBRequest and EventTarget, can also be dispatched on IDBOpenDBRequest objects.

Listen to these generic and specific events using addEventListener() or by assigning an event listener to the oneventname property of this interface.

Events specific to this interface are:


Fired when an open connection to a database is blocking a versionchange transaction on the same database. Also available via the onblocked property.


Fired when an attempt was made to open a database with a version number higher than its current version. Also available via the onupgradeneeded property.


In the following example you can see the onupgradeneeded handler being used to update the database structure if a database with a higher version number is loaded. For a full working example, see our To-do Notifications app (view example live.)

let db;

// Let us open our database
const DBOpenRequest ="toDoList", 4);

// these event handlers act on the database being opened.
DBOpenRequest.onerror = (event) => {
  note.innerHTML += "<li>Error loading database.</li>";

DBOpenRequest.onsuccess = (event) => {
  note.innerHTML += "<li>Database initialized.</li>";

  // store the result of opening the database in the db
  // variable. This is used a lot below
  db = DBOpenRequest.result;

  // Run the displayData() function to populate the task
  // list with all the to-do list data already in the IDB

// 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 line above
// it is only implemented in recent browsers
DBOpenRequest.onupgradeneeded = (event) => {
  const db =;

  db.onerror = (event) => {
    note.innerHTML += "<li>Error loading database.</li>";

  // Create an objectStore for this database
  const 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 });
  objectStore.createIndex("notified", "notified", { unique: false });


Indexed Database API 3.0
# idbopendbrequest

Browser compatibility

BCD tables only load in the browser

See also