The openKeyCursor() method of the IDBIndex interface returns an IDBRequest object, and, in a separate thread, creates a cursor over the specified key range, as arranged by this index.

The method sets the position of the cursor to the appropriate key, based on the specified direction.

  • If the key range is not specified or is null, then the range includes all the keys.
  • If at least one key matches the key range, then a success event is fired on the result object, with its result set to the new IDBCursor object; the value of the cursor object is set to the value of the found record.
  • If no keys ranges match the key range specified, then then an error event is fired on the request object.

Note: This feature is available in Web Workers.


var myIndex = objectStore.index('index');
var request = myIndex.openKeyCursor(range,direction);


An IDBRequest object on which subsequent events related to this operation are fired.


This method may raise a DOMException of one of the following types:

Exception Description
TransactionInactiveError This IDBIndex's transaction is inactive.
TypeError The value for the direction parameter is invalid.

The key or key range provided contains an invalid key.

InvalidStateError The IDBIndex has been deleted or removed.


Important: This example does not yet work. Research is currently being done on this method, and more useful information will be available soon.

In the following example we open a transaction and an object store, then get the index lName from a simple contacts database. We then open a key cursor on the index using openKeyCursor() — this works the same as opening a cursor directly on an ObjectStore using IDBObjectStore.openCursor except that the returned records are sorted based on the index, not the primary key.

Finally, we iterate through each record, and insert the data into an HTML table. For a complete working example, see our IDBIndex-example demo repo (View the example live.)

function displayDataByIndex() {
  tableEntry.innerHTML = '';
  var transaction = db.transaction(['contactsList'], 'readonly');
  var objectStore = transaction.objectStore('contactsList');

  var myIndex = objectStore.index('lName'); 

  myIndex.openKeyCursor().onsuccess = function(event) {
    var cursor =;
    if(cursor) {
      var tableRow = document.createElement('tr');
      tableRow.innerHTML =   '<td>' + + '</td>'
                           + '<td>' + cursor.value.lName + '</td>'
                           + '<td>' + cursor.value.fName + '</td>'
                           + '<td>' + cursor.value.jTitle + '</td>'
                           + '<td>' + + '</td>'
                           + '<td>' + cursor.value.eMail + '</td>'
                           + '<td>' + + '</td>'
                           + '<td>' + cursor.value.age + '</td>';

    } else {
      console.log('Entries all displayed.');    


range Optional
A key or IDBKeyRange to use as the cursor's range. If nothing is passed, this will default to a key range that selects all the records in this object store.
direction Optional
The cursor's direction. See IDBCursor Constants for possible values.


Specification Status Comment
Indexed Database API
The definition of 'openKeyCursor()' in that specification.
Editor's Draft  

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari (WebKit)
Basic support 23webkit
10 moz
16.0 (16.0)
10, partial 15 7.1
Available in workers (Yes) 37.0 (37.0) ? (Yes) ?
Feature Android Firefox Mobile (Gecko) Firefox OS IE Phone Opera Mobile Safari Mobile
Basic support 4.4 22.0 (22.0) 1.0.1 10 22 8
Available in workers (Yes) 37.0 (37.0) (Yes) ? (Yes) ?

See also



Document Tags and Contributors

 Contributors to this page: jpmedley, inexorabletash, chrisdavidmills, fscholz
 Last updated by: jpmedley,