# .ajaxStart()

## ajaxStart ( handler() ) Returns: jQuery version added: 1.0

- handler()
  Type: Function
  The function to be invoked.

Description: Register a handler to be called when the first Ajax request begins. This is an Ajax Event.

Whenever an Ajax request is about to be sent, jQuery checks whether there are any other outstanding Ajax requests. If none are in progress, jQuery triggers the `ajaxStart` event. Any and all handlers that have been registered with the `.ajaxStart()` method are executed at this time.

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

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

Attach the event handler to any element:

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

Now, make an Ajax request using any jQuery method:

    $( ".trigger" ).click(function() {
      $( ".result" ).load( "ajax/test.html" );
    });

When the user clicks the element with class `trigger` and the Ajax request is sent, the log message is displayed.

As of jQuery 1.8, the `.ajaxStart()` method should only be attached to `document`.

## Examples:

#### Example: Show a loading message whenever an Ajax request starts (and none is already active).

    $( document ).ajaxStart(function() {
      $( "#loading" ).show();
    });