IDBRequest.onerror - Web APIs 编辑

The onerror event handler of the IDBRequest interface handles the error event, fired when a request returns an error.

The event handler takes one parameter, an error Event with type="error".

Note:

Syntax

request.onerror = function(event) { ... };

Example

The following example requests a given record title, onsuccess gets the associated record from the IDBObjectStore (made available as objectStoreTitleRequest.result), updates one property of the record, and then puts the updated record back into the object store. Also included at the bottom is an onerror function that reports what the error was if the request fails. For a full working example, see our To-do Notifications app (view example live.)

var title = "Walk dog";

// Open up a transaction as usual
var objectStore = db.transaction(['toDoList'], "readwrite").objectStore('toDoList');

// Get the to-do list object that has this title as it's title
var objectStoreTitleRequest = objectStore.get(title);

objectStoreTitleRequest.onsuccess = function() {
  // Grab the data object returned as the result
  var data = objectStoreTitleRequest.result;

  // Update the notified value in the object to "yes"
  data.notified = "yes";

  // Create another request that inserts the item back
  // into the database
  var updateTitleRequest = objectStore.put(data);

  // When this new request succeeds, run the displayData()
  // function again to update the display
  updateTitleRequest.onsuccess = function() {
    displayData();
  };
};

objectStoreTitleRequest.onerror = function() {
  // If an error occurs with the request, log what it is
  console.log("There has been an error with retrieving your data: " + objectStoreTitleRequest.error);
  // TODO what about event parameter into onerror()? What will be inside of this event?
};

Specifications

Browser compatibility

BCD tables only load in the browser

See also

• Using IndexedDB
• Error Event
• 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.)