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IDBCursor.key

The key read-only property of the IDBCursor interface returns the key for the record at the cursor's position. If the cursor is outside its range, this is set to undefined. The cursor's key can be any data type.

Note: This feature is available in Web Workers.

Syntax

var key = cursor.key;

Value

A value of any type.

Example

In this simple fragment we create a transaction, retrieve an object store, then use a cursor to iterate through all the records in the object store. Within each iteration we log the key of the cursor to the console, something like this (its the album title in each case, which is our key).

The cursor does not require us to select the data based on a key; we can just grab all of it. Also note that in each iteration of the loop, you can grab data from the current record under the cursor object using cursor.value.foo. For a complete working example, see our IDBCursor example (view example live.)

function displayData() {
  var transaction = db.transaction(['rushAlbumList'], "readonly");
  var objectStore = transaction.objectStore('rushAlbumList');

  objectStore.openCursor().onsuccess = function(event) {
    var cursor = event.target.result;
    if(cursor) {
      var listItem = document.createElement('li');
      listItem.innerHTML = cursor.value.albumTitle + ', ' + cursor.value.year;
      list.appendChild(listItem);  
      
      console.log(cursor.key);
      cursor.continue();
    } else {
      console.log('Entries all displayed.');
    }
  };
};

Specifications

Specification Status Comment
Indexed Database API
The definition of 'key' in that specification.
Recommendation  
Indexed Database API 2.0
The definition of 'key' in that specification.
Editor's Draft  

Browser compatibility

Feature Chrome Edge Firefox (Gecko) Internet Explorer Opera Safari (WebKit)
Basic support 23webkit
24
(Yes) 10 moz
16.0 (16.0)
10, partial 15 7.1
Available in workers (Yes) (Yes) 37.0 (37.0) ? (Yes) ?
Binary keys ? ? 51.0 (51.0) ? ? ?
Indexed Database 2.0 58 ? ? ? 45 ?
Feature Android Webview Chrome for Android Edge Firefox Mobile (Gecko) IE Phone Opera Mobile Safari Mobile
Basic support (Yes) (Yes) (Yes) 22.0 (22.0) 10 22 8
Available in workers (Yes) (Yes) (Yes) 37.0 (37.0) ? (Yes) ?
Binary keys ? ? ? 51.0 (51.0) ? ? ?
Indexed Database 2.0 58 58 ? ? ? 45 ?

See also

Document Tags and Contributors

 Contributors to this page: jpmedley, arronei, libbymc, teoli, chrisdavidmills, trevorh, DevelX, linkwisdom
 Last updated by: jpmedley,