The getKey() method of the IDBIndex interface returns an IDBRequest object, and, in a separate thread, finds either the given key or the primary key, if key is set to an IDBKeyRange.

If a key is successfully found it is set as the result of the request object: this returns the primary key of the record the key is associated with, not the whole record as IDBIndex.get does.

Note: This feature is available in Web Workers.


var myIndex = objectStore.index('index');
var request = myIndex.getKey(key);


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.

The key or key range provided contains an invalid key.

InvalidStateError The IDBIndex has been deleted or removed.


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 basic cursor on the index using IDBIndex.openCursor — 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.

myIndex.getKey('Bungle') is then used to retrieve the primary key of the record with an lName of Bungle, and the result of that request is logged to the console when its success callback returns.

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'); 
  var getKeyRequest = myIndex.getKey('Bungle');
  getKeyRequest.onsuccess = function() {

  myIndex.openCursor().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.');    


key Optional
A key or IDBKeyRange that identifies a record to be retrieved. If this value is null or missing, the browser will use an unbound key range.


Specification Status Comment
Indexed Database API
The definition of 'getKey()' 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,