Web/API/IDBCursor

Note: Not to be confused with IDBCursorWithValue which is just an IDBCursor interface with an additional value property.

The IDBCursor interface of the IndexedDB API represents a cursor for traversing or iterating over multiple records in a database.

The cursor has a source that indicates which index or object store it is iterating over. It has a position within the range, and moves in a direction that is increasing or decreasing in the order of record keys. The cursor enables an application to asynchronously process all the records in the cursor's range.

You can have an unlimited number of cursors at the same time. You always get the same IDBCursor object representing a given cursor. Operations are performed on the underlying index or object store.

Note: This feature is available in Web Workers.

Properties

Note: IDBCursorWithValue is an IDBCursor interface with an additional value property.

IDBCursor.source Read only: Returns the IDBObjectStore or IDBIndex that the cursor is iterating. This function never returns null or throws an exception, even if the cursor is currently being iterated, has iterated past its end, or its transaction is not active.
IDBCursor.direction Read only: Returns the direction of traversal of the cursor. See Constants for possible values.
IDBCursor.key Read only: 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.
IDBCursor.primaryKey Read only: Returns the cursor's current effective primary 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.
IDBCursor.request Read only: Returns the IDBRequest that was used to obtain the cursor.

Methods

IDBCursor.advance(): Sets the number of times a cursor should move its position forward.
IDBCursor.continue(): Advances the cursor to the next position along its direction, to the item whose key matches the optional key parameter.
IDBCursor.continuePrimaryKey(): Sets the cursor to the given index key and primary key given as arguments.

IDBCursor.delete(): Returns an IDBRequest object, and, in a separate thread, deletes the record at the cursor's position, without changing the cursor's position. This can be used to delete specific records.
IDBCursor.update(): Returns an IDBRequest object, and, in a separate thread, updates the value at the current position of the cursor in the object store. This can be used to update specific records.

Constants

Deprecated since Gecko 13 (Firefox 13 / Thunderbird 13 / SeaMonkey 2.10)This feature is no longer recommended. Though some browsers might still support it, it may have already been removed from the relevant web standards, may be in the process of being dropped, or may only be kept for compatibility purposes. Avoid using it, and update existing code if possible; see the compatibility table at the bottom of this page to guide your decision. Be aware that this feature may cease to work at any time.

These constants are no longer available — they were removed in Gecko 25. You should use the string constants directly instead. (bug 891944)

NEXT : "next" : The cursor shows all records, including duplicates. It starts at the lower bound of the key range and moves upwards (monotonically increasing in the order of keys).
NEXTUNIQUE : "nextunique" : The cursor shows all records, excluding duplicates. If multiple records exist with the same key, only the first one iterated is retrieved. It starts at the lower bound of the key range and moves upwards.
PREV : "prev" : The cursor shows all records, including duplicates. It starts at the upper bound of the key range and moves downwards (monotonically decreasing in the order of keys).
PREVUNIQUE : "prevunique" : The cursor shows all records, excluding duplicates. If multiple records exist with the same key, only the first one iterated is retrieved. It starts at the upper bound of the key range and moves downwards.

Examples

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. 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 ([[../../../../../../mdn.github.io/indexeddb-examples/idbcursor/index|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);  

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

Specifications

Specification	Status	Comment
Indexed Database API 2.0The definition of 'cursor' in that specification.	Recommendation	Initial definition
Indexed Database API DraftThe definition of 'cursor' in that specification.	Recommendation	Added `continuePrimaryKey()` and support for binary keys, and the `IDBCursor.request` property.

Browser compatibility

Update compatibility data on GitHub

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
`IDBCursor`	Chrome Full support 24 Full support 24 No support 23 — 57 Prefixed' Prefixed' Implemented with the vendor prefix: webkit	Edge Full support 12	Firefox Full support 16 Full support 16 No support 10 — 16 Prefixed' Prefixed' Implemented with the vendor prefix: moz	IE Partial support 10	Opera Full support 44 Full support 44 No support 15 — 44 Prefixed' Prefixed' Implemented with the vendor prefix: webkit	Safari Full support 7	WebView Android Full support Yes Full support Yes No support ? — 57 Prefixed' Prefixed' Implemented with the vendor prefix: webkit	Chrome Android Full support 25 Full support 25 No support 25 — 57 Prefixed' Prefixed' Implemented with the vendor prefix: webkit	Firefox Android Full support 22	Opera Android Full support 43 Full support 43 No support 14 — 43 Prefixed' Prefixed' Implemented with the vendor prefix: webkit	Safari iOS Full support 8	Samsung Internet Android Full support 1.5 Full support 1.5 No support 1.5 — 7.0 Prefixed' Prefixed' Implemented with the vendor prefix: webkit
`advance`	Chrome Full support 24 Full support 24 No support 23 — 24 Prefixed' Prefixed' Implemented with the vendor prefix: webkit	Edge Full support 12	Firefox Full support 16 Full support 16 No support 10 — 16 Prefixed' Prefixed' Implemented with the vendor prefix: moz	IE Partial support 10	Opera Full support 15	Safari Full support 7	WebView Android Full support Yes	Chrome Android Full support Yes	Firefox Android Full support 22	Opera Android Full support 14	Safari iOS Full support 8	Samsung Internet Android Full support Yes
`continue`	Chrome Full support 24 Full support 24 No support 23 — 24 Prefixed' Prefixed' Implemented with the vendor prefix: webkit	Edge Full support 12	Firefox Full support 16 Full support 16 No support 10 — 16 Prefixed' Prefixed' Implemented with the vendor prefix: moz	IE Partial support 10	Opera Full support 15	Safari Full support 7	WebView Android Full support Yes	Chrome Android Full support Yes	Firefox Android Full support 22	Opera Android Full support 14	Safari iOS Full support 8	Samsung Internet Android Full support Yes
`continuePrimaryKey`	Chrome Full support 58	Edge Full support 79	Firefox Full support 51 Full support 51 No support 10 — 51 Prefixed' Prefixed' Implemented with the vendor prefix: moz	IE No support No	Opera Full support 45	Safari Full support 10.1	WebView Android Full support 58	Chrome Android Full support 58	Firefox Android Full support 51	Opera Android Full support 43	Safari iOS Full support 10.3	Samsung Internet Android Full support 7.0
`delete`	Chrome Full support 24 Full support 24 No support 23 — 24 Prefixed' Prefixed' Implemented with the vendor prefix: webkit	Edge Full support 12	Firefox Full support 16 Full support 16 No support 10 — 16 Prefixed' Prefixed' Implemented with the vendor prefix: moz	IE Partial support 10	Opera Full support 15	Safari Full support 7	WebView Android Full support Yes	Chrome Android Full support Yes	Firefox Android Full support 22	Opera Android Full support 14	Safari iOS Full support 8	Samsung Internet Android Full support Yes
`direction`	Chrome Full support 24 Full support 24 No support 23 — 24 Prefixed' Prefixed' Implemented with the vendor prefix: webkit	Edge Full support 12	Firefox Full support 16 Full support 16 No support 10 — 16 Prefixed' Prefixed' Implemented with the vendor prefix: moz	IE Partial support 10	Opera Full support 15	Safari Full support 7	WebView Android Full support Yes	Chrome Android Full support Yes	Firefox Android Full support 22	Opera Android Full support 14	Safari iOS Full support 8	Samsung Internet Android Full support Yes
`key`	Chrome Full support 24 Full support 24 No support 23 — 24 Prefixed' Prefixed' Implemented with the vendor prefix: webkit	Edge Full support 12	Firefox Full support 16 Full support 16 No support 10 — 16 Prefixed' Prefixed' Implemented with the vendor prefix: moz	IE Partial support 10	Opera Full support 15	Safari Full support 7	WebView Android Full support Yes	Chrome Android Full support Yes	Firefox Android Full support 22	Opera Android Full support 14	Safari iOS Full support 8	Samsung Internet Android Full support Yes
`primaryKey`	Chrome Full support 24 Full support 24 No support 23 — 24 Prefixed' Prefixed' Implemented with the vendor prefix: webkit	Edge Full support 12	Firefox Full support 16 Full support 16 No support 10 — 16 Prefixed' Prefixed' Implemented with the vendor prefix: moz	IE Partial support 10	Opera Full support 15	Safari Full support 7	WebView Android Full support Yes	Chrome Android Full support Yes	Firefox Android Full support 22	Opera Android Full support 14	Safari iOS Full support 8	Samsung Internet Android Full support Yes
`request`	Chrome Full support 76	Edge Full support 79	Firefox Full support 77	IE No support No	Opera Full support 63	Safari ?	WebView Android Full support 76	Chrome Android Full support 76	Firefox Android No support No	Opera Android Full support 54	Safari iOS ?	Samsung Internet Android Full support 12.0
`source`	Chrome Full support 24 Full support 24 No support 23 — 24 Prefixed' Prefixed' Implemented with the vendor prefix: webkit	Edge Full support 12	Firefox Full support 16 Full support 16 No support 10 — 16 Prefixed' Prefixed' Implemented with the vendor prefix: moz	IE Partial support 10	Opera Full support 15	Safari Full support 7	WebView Android Full support Yes	Chrome Android Full support Yes	Firefox Android Full support 22	Opera Android Full support 14	Safari iOS Full support 8	Samsung Internet Android Full support Yes
`update`	Chrome Full support 24 Full support 24 No support 23 — 24 Prefixed' Prefixed' Implemented with the vendor prefix: webkit	Edge Full support 12	Firefox Full support 16 Full support 16 No support 10 — 16 Prefixed' Prefixed' Implemented with the vendor prefix: moz	IE Partial support 10	Opera Full support 15	Safari Full support 7	WebView Android Full support Yes	Chrome Android Full support Yes	Firefox Android Full support 22	Opera Android Full support 14	Safari iOS Full support 8	Samsung Internet Android Full support Yes
Available in workers	Chrome Full support 24 Full support 24 No support 23 — 57 Prefixed' Prefixed' Implemented with the vendor prefix: webkit	Edge Full support ≤18	Firefox Full support 37	IE ?	Opera Full support 44 Full support 44 No support 15 — 44 Prefixed' Prefixed' Implemented with the vendor prefix: webkit	Safari Full support 7	WebView Android Full support Yes Full support Yes No support ? — 57 Prefixed' Prefixed' Implemented with the vendor prefix: webkit	Chrome Android Full support 25 Full support 25 No support 25 — 57 Prefixed' Prefixed' Implemented with the vendor prefix: webkit	Firefox Android Full support 37	Opera Android Full support Yes Full support Yes No support 14 — 43 Prefixed' Prefixed' Implemented with the vendor prefix: webkit	Safari iOS ?	Samsung Internet Android Full support 1.5 Full support 1.5 No support 1.5 — 7.0 Prefixed' Prefixed' Implemented with the vendor prefix: webkit

Legend

Full support: Full support
Partial support: Partial support
No support: No support
Compatibility unknown: Compatibility unknown
Requires a vendor prefix or different name for use.': Requires a vendor prefix or different name for use.