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The primaryKey read-only property of the IDBCursor interface returns the cursor's current effective key. If the cursor is currently being iterated or has iterated outside its range, this is set to undefined. The cursor's primary key can be any data type.

Note: This feature is available in Web Workers.


var value = cursor.primaryKey;


A value of any data type.


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 primary key of the cursor to the console, something like this (its the album title in each case, which is our primarykey):


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


Specification Status Comment
Indexed Database API
The definition of 'primaryKey' in that specification.
Indexed Database API 2.0
The definition of 'primaryKey' in that specification.

Browser compatibility

FeatureChromeEdgeFirefoxInternet ExplorerOperaSafari
Basic support


23 — 24 webkit



10 — 16 moz

FeatureAndroid webviewChrome for AndroidEdge mobileFirefox for AndroidOpera AndroidiOS SafariSamsung Internet
Basic support Yes Yes Yes22228 ?

1. partial

See also

Etiquetas y colaboradores del documento

 Colaboradores en esta página: fscholz, jpmedley, arronei, libbymc, chrisdavidmills, teoli
 Última actualización por: fscholz,