The onversionchange event handler of the IDBDatabase interface handles the versionchange event, fired when a database structure change (IDBOpenDBRequest.onupgradeneeded event or IDBFactory.deleteDatabase) was requested elsewhere (most probably in another window/tab on the same computer).

This is different from the versionchange transaction (but it is related).


This feature is available in Web Workers.


IDBDatabase.onversionchange = function(event) { ... }


This example shows an IDBOpenDBRequest.onupgradeneeded block that creates a new object store; it also includes onerror and onabort functions to handle non-success cases, and an onversionchange function to notify when a database structure change has occurred.

request.onupgradeneeded = function(event) {
  var db =;

  db.onerror = function(event) {
    note.innerHTML += '<li>Error opening database.</li>';

  db.onabort = function(event) {
    note.innerHTML += '<li>Database opening aborted!</li>';

  // 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 });

  objectStore.createIndex("notified", "notified", { unique: false });

  note.innerHTML += '<li>Object store created.</li>';

  db.onversionchange = function(event) {
    note.innerHTML += '<li>a database change has occurred; you should refresh this
                       browser window, or close it down and use the other open version of
                       this application, wherever it exists.</li>';


Browser compatibility

BCD tables only load in the browser

See also