Example

In the following code snippet, we open a database asynchronously and make a request.  Because the specification is still evolving, Chrome and Firefox put prefixes in the methods. Chrome uses the webkit prefix while Firefox uses the moz prefix. Event handlers are registered for responding to various situations.

// Taking care of the browser-specific prefixes.
if ('webkitIndexedDB' in window) {
   window.indexedDB = window.webkitIndexedDB;
   window.IDBTransaction = window.webkitIDBTransaction;
} else if ('mozIndexedDB' in window) {
   window.indexedDB = window.mozIndexedDB;
}

//Open a connection to the database with the name "creatures" 
//with the empty string as its version.  

var creatures = {};
creatures.indexedDB = {};

creatures.indexedDB.open = function() {
  var request = indexedDB.open("creatures");

  //The open request isn't executed yet, but an IDBRequest object is returned. 
  //Create listeners to the IDBRequest. 
  //If the open request is successful, the onsuccess callback is executed. 

  request.onsuccess = function(event) {
    var version = "1.0 beta";
    creatures.indexedDB.db = event.target.result;
    var db = creatures.indexedDB.db;

    //Check the database version, which is a string. 
    //If it isn't the expected version, call setVersion().     
    //setVersion() is where you can create and delete object stores and indexes. 
    
    if(version != db.version) {
      var setVersionRequest = db.setVersion(version);

      // setVersion() returns IDBRequest object.
      // Attach callbacks to IDBRequest. 

      setVersionRequest.onsuccess = function(event) {

        // If it's successful, create an object store called "swamp"
        // and define an optional parameter object, the "terrorizedPopulace" keyPath.        
        // The keyPath must be what makes an object unique and every object must have it.  
        // If every creature had a unique identification number, that would also be a good keyPath. 
        
        var datastore = db.createObjectStore("swamp",
          {keyPath: "terrorizedPopulace"});

       setVersionRequest.onfailure = creatures.indexedDB.onerror;  

        //After the object store is created, call the method, getAllSwampCreatures. 
        creatures.indexedDB.getAllSwampCreatures();
      };
                  
    }

    creatures.indexedDB.getAllSwampCreatures();
  };

  request.onfailure = creatures.indexedDB.onerror;
}

Example

The following is an example of how to open a read-write transaction.

//Open a transaction with a scope of data stores and a read-write mode.
var trans = db.transaction(['list-of-store-names'], IDBTransaction.READ_WRITE);

//"objectStore()" is an IDBTransaction method that returns an object store 
//that has already been added to the scope of the transaction.  
var store = trans.objectStore('your-store-name');
   var req = store.put(value, key); 
   req.onsuccess = ...; 
   req.onerror = ...;

Parameters

name

The name of the new object store.

optionalParameters

Warning: The latest draft of the specification changed this to IDBDatabaseOptionalParameters, which is not yet recognized by any browser

Optional. Options object whose attributes are optional parameters to the method. It includes the following properties:

Attribute	Description
keyPath	The key path to be used by the new object store. If empty or not specified, the object store is created without a key path and uses out-of-line keys.
autoIncrement	If true, the object store has a key generator. Defaults to false.

Returns

IDBObjectStore

The newly created object store.

Exceptions

This method can raise an IDBDatabaseException with the following codes:

Parameters

name

The name of the data store to delete.

Returns

void

Exceptions

This method can raise an IDBDatabaseException with the following codes:

Parameters

version

The version to store in the database.

Returns

IDBVersionChangeRequest

The request to change the version of a database.

Parameters

storeNames

The names of object stores and indexes that are in the scope of the new transaction.

mode

Optional. The types of access that can be performed in the transaction. Transactions are opened in one of three modes: READ_ONLY, READ_WRITE, and VERSION_CHANGE. If you don't provide the parameter, the default access mode is READ_ONLY.

Returns

IDBTransaction

The transaction object

Exceptions

This method can raise an IDBDatabaseException with the following codes: