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    The index() method of the IDBObjectStore interface opens a named index in the current object store, after which it can be used to, for example, return a series of records sorted by that index using a cursor. 




    An IDBIndex object for accessing the index.


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

    Exception Description
    InvalidStateError The source object store has been deleted, or the transaction for the object store has finished.
    NotFoundError There is no index with the given name (case-sensitive) in the database.


    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.

    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.');    


    The name of the index to open.


    Specification Status Comment
    Indexed Database API
    The definition of 'index()' in that specification.
    Candidate Recommendation  

    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
    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 Not supported

    See also

    Document Tags and Contributors

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