IDBCursor.advance

The advance() method of the IDBCursor interface sets the number of times a cursor should move its position forward.

Syntax

cursor.advance(count);

Parameters

count

The number of times to move the cursor forward.

Returns

Void.

Exceptions

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

Exception	Description
TransactionInactiveError	This IDBCursor's transaction is inactive.
TypeError	The value passed into the count parameter was zero or a negative number.
InvalidStateError	The cursor is currently being iterated or has iterated past its end.

Example

In this simple fragment we create a transaction, retrieve an object store, then use a cursor to iterate through the records in the object store. Here we use cursor.advance(2) to jump 2 places forward each time, meaning that only every other result will be displayed. advance() works in a similar way to IDBCursor.continue, except that it allows you to jump multiple records at a time, not just always go onto the next record.

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 advanceResult() {
  list.innerHTML = '';
  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 = '<strong>' + cursor.value.albumTitle + '</strong>, ' + cursor.value.year;
      list.appendChild(listItem);  
      cursor.advance(2);
    } else {
      console.log('Every other entry displayed.');
    }
  };
};

Specifications

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

Browser compatibility

See also

• Using IndexedDB
• Starting transactions: IDBDatabase
• Using transactions: IDBTransaction
• Setting a range of keys: IDBKeyRange
• Retrieving and making changes to your data: IDBObjectStore
• Using cursors: IDBCursor
• Reference example: To-do Notifications (view example live.)