## .ajaxError( handler )Returns: jQuery

Description: Register a handler to be called when Ajax requests complete with an error. This is an Ajax Event.

- #### version added: 1.0.ajaxError( handler )

  - handler
    Type: Function( Event event, jqXHR jqXHR, PlainObject ajaxSettings, String thrownError )
    The function to be invoked.

Whenever an Ajax request completes with an error, jQuery triggers the `ajaxError` event. Any and all handlers that have been registered with the `.ajaxError()` method are executed at this time. Note: This handler is not called for cross-domain script and cross-domain JSONP requests.

To observe this method in action, set up a basic Ajax load request.

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    <button class="trigger">Trigger</button><div class="result"></div><div class="log"></div>

Attach the event handler to the document:

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    $( document ).ajaxError(function() {  $( ".log" ).text( "Triggered ajaxError handler." );});

Now, make an Ajax request using any jQuery method:

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    $( "button.trigger" ).on( "click", function() {  $( "div.result" ).load( "ajax/missing.html" );});

When the user clicks the button and the Ajax request fails, because the requested file is missing, the log message is displayed.

All `ajaxError` handlers are invoked, regardless of what Ajax request was completed. To differentiate between the requests, use the parameters passed to the handler. Each time an `ajaxError` handler is executed, it is passed the event object, the `jqXHR` object (prior to jQuery 1.5, the `XHR` object), and the settings object that was used in the creation of the request. When an HTTP error occurs, the fourth argument (`thrownError`) receives the textual portion of the HTTP status, such as "Not Found" or "Internal Server Error." For example, to restrict the error callback to only handling events dealing with a particular URL:

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    $( document ).ajaxError(function( event, jqxhr, settings, thrownError ) {  if ( settings.url == "ajax/missing.html" ) {    $( "div.log" ).text( "Triggered ajaxError handler." );  }});

### Additional Notes:

- As of jQuery 1.9, all the handlers for the jQuery global Ajax events, including those added with the `.ajaxError()` method, must be attached to `document`.
- If `$.ajax()` or `$.ajaxSetup()` is called with the `global` option set to `false`, the `.ajaxError()` method will not fire.

## Example:

Show a message when an Ajax request fails.

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    $( document ).ajaxError(function( event, request, settings ) {  $( "#msg" ).append( "<li>Error requesting page " + settings.url + "</li>" );});