IDBIndex.openCursor()

The openCursor() method of the IDBIndex interface returns an IDBRequest object, and, in a separate thread, creates a cursor over the specified key range.

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

If the key range is not specified or is null, then the range includes all the records.

Note: This feature is available in Web Workers

Syntax

var request = myIndex.openCursor();
var request = myIndex.openCursor(range);
var request = myIndex.openCursor(range, direction);

Parameters

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.

Return value

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

Exceptions

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.
DataError The key or key range provided contains an invalid key.
InvalidStateError The IDBIndex has been deleted or removed.

Example

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 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 IndexedDB-examples 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 = event.target.result;
    if(cursor) {
      var tableRow = document.createElement('tr');
      tableRow.innerHTML =   '<td>' + cursor.value.id + '</td>'
                           + '<td>' + cursor.value.lName + '</td>'
                           + '<td>' + cursor.value.fName + '</td>'
                           + '<td>' + cursor.value.jTitle + '</td>'
                           + '<td>' + cursor.value.company + '</td>'
                           + '<td>' + cursor.value.eMail + '</td>'
                           + '<td>' + cursor.value.phone + '</td>'
                           + '<td>' + cursor.value.age + '</td>';
      tableEntry.appendChild(tableRow);

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

Specifications

Browser compatibility

Desktop Mobile
Chrome Edge Firefox Internet Explorer Opera Safari WebView Android Chrome Android Firefox for Android Opera Android Safari on IOS Samsung Internet
openCursor
23
12
10
10
15
7
≤37
25
22
14
8
1.5

See also

© 2005–2021 MDN contributors.
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/API/IDBIndex/openCursor