requestonsuccess

Request.onsuccess is a callback property of the IDBRequest interface used in the IndexedDB API to handle the successful completion of a database operation. It is commonly assigned to respond to operations such as add, put, delete, get, or cursor-related requests. When the operation completes without error, the onsuccess handler is invoked with an event object.

Within the onsuccess handler, the result of the operation can be accessed via event.target.result (or via request.result in some contexts). This value represents the data retrieved or the outcome of the operation, such as the stored object for a get request or the key for an add/put operation. The handler runs after the underlying transaction has progressed to a successful state, and it is typically used to continue application logic that depends on the retrieved data or confirmation of the operation.

The request.onsuccess handler can be defined in two common ways: by assigning a function directly to the onsuccess property, or by attaching an event listener for the 'success' event via addEventListener. For example, a get request might set request.onsuccess = function(event) { console.log(event.target.result); }; or use request.addEventListener('success', function(event) { ... }); The latter approach offers greater flexibility in managing multiple listeners.

Compatibility and behavior: onsuccess is part of the standard IndexedDB API and is supported in major browsers. Errors are handled separately with onerror, and the transaction’s overall progress is governed by the transaction's lifecycle and error handling strategies.