The keyPath property of the IDBIndex interface returns the key path of the current index. If null, this index is not auto-populated.

Note: This feature is available in Web Workers.


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


Any data type that can be used as a key path.


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.

The key path of the current index is logged to the console: it should be returned as lName.

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.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.');    


Specification Status Comment
Indexed Database API
The definition of 'keyPath' 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, chrisdavidmills, freaktechnik, fscholz
 Last updated by: jpmedley,