This example shows an IDBOpenDBRequest.onupgradeneeded block that creates a new object store; it also includes onerror and onabort functions to handle non-success cases.
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. Note the transaction.onabort = function(event) { }; block, reporting when the transaction has been aborted. For a full working example, see our To-do Notifications app (view example live.)