IDBTransaction.mode

The mode read-only property of the IDBTransaction interface returns the current mode for accessing the data in the object stores in the scope of the transaction (i.e. is the mode to be read-only, or do you want to write to the object stores?) The default value is readonly.

Note: This feature is available in Web Workers.

Syntax

var myCurrentMode = IDBTransaction.mode;

Value

An IDBTransactionMode object defining the mode for isolating access to data in the current object stores:

Value Explanation
readonly Allows data to be read but not changed.
readwrite Allows reading and writing of data in existing data stores to be changed.
versionchange Allows any operation to be performed, including ones that delete and create object stores and indexes. This mode is for updating the version number of transactions that were started using IDBDatabase.setVersion(). Transactions of this mode cannot run concurrently with other transactions. Transactions in this mode are known as "upgrade transactions."

Example

In the following code snippet, we open a read/write transaction on our database and add some data to an object store. Note also the functions attached to transaction event handlers to report on the outcome of the transaction opening in the event of success or failure. At the end, we simply log the mode of the current transaction using mode. For a full working example, see our To-do Notifications app (view example live.)

// Let us open our database
var DBOpenRequest = window.indexedDB.open("toDoList", 4);

DBOpenRequest.onsuccess = function(event) {
  note.innerHTML += '<li>Database initialised.</li>';
    
  // store the result of opening the database in the db variable.
  // This is used a lot below
  db = DBOpenRequest.result;
    
  // Run the addData() function to add the data to the database
  addData();
};

function addData() {
  // Create a new object ready for being inserted into the IDB
  var newItem = [ { taskTitle: "Walk dog", hours: 19, minutes: 30, day: 24, month: "December", year: 2013, notified: "no" } ];

  // open a read/write db transaction, ready for adding the data
  var transaction = db.transaction(["toDoList"], "readwrite");

  // report on the success of opening the transaction
  transaction.oncomplete = function(event) {
    note.innerHTML += '<li>Transaction completed: database modification finished.</li>';
  };

  transaction.onerror = function(event) {
    note.innerHTML += '<li>Transaction not opened due to error. Duplicate items not allowed.</li>';
  };

  // create an object store on the transaction
  var objectStore = transaction.objectStore("toDoList");

  // add our newItem object to the object store
  var objectStoreRequest = objectStore.add(newItem[0]);

  objectStoreRequest.onsuccess = function(event) {
    // report the success of the request (this does not mean the item
    // has been stored successfully in the DB - for that you need transaction.onsuccess)
    note.innerHTML += '<li>Request successful.</li>';
  };

  // Return the mode this transaction has been opened in (should be "readwrite" in this case)
  transaction.mode;
};

Specification

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

Browser compatibility

Update compatibility data on GitHub
DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidEdge MobileFirefox for AndroidOpera for AndroidiOS SafariSamsung Internet
Basic supportChrome Full support 24
Full support 24
Full support 23
Prefixed
Prefixed Requires the vendor prefix: webkit
Edge Full support 12Firefox Full support 16
Full support 16
No support 10 — 16
Prefixed
Prefixed Requires the vendor prefix: moz
IE Full support 10
Notes
Full support 10
Notes
Notes partial
Opera Full support 15Safari Full support 7WebView Android Full support YesChrome Android Full support YesEdge Mobile Full support YesFirefox Android Full support 22Opera Android Full support 22Safari iOS Full support 8Samsung Internet Android Full support Yes

Legend

Full support  
Full support
See implementation notes.
See implementation notes.
Requires a vendor prefix or different name for use.
Requires a vendor prefix or different name for use.

See also

Document Tags and Contributors

Contributors to this page: fscholz, chrisdavidmills, jpmedley, libbymc, Sheppy
Last updated by: fscholz,