Most modern browsers include the native method navigator.sendBeacon(). It asynchronously sends a small amount of data over HTTP to a web server. AppMeasurement can use the navigator.sendBeacon() method if the useBeacon variable is enabled. It is useful for exit links and other situations where you want to send information before the page unloads.

If useBeacon is enabled, the next hit sent to Adobe uses the browser’s navigator.sendBeacon() method instead of a standard GET image request. This variable applies to both s.t() and image requests. It requires AppMeasurement 2.17.0 or higher.

AppMeasurement automatically enables useBeacon for exit link image requests.

The useBeacon variable is ignored when the visitor uses a browser that does not support navigator.sendBeacon(). Use of this variable requires AppMeasurement 2.16.0 or higher.

Use the sendBeacon API using the Web SDK extension

The Document will unload checkbox within an Action Configuration determines if data sent to Adobe uses the sendBeacon API.

  1. Log in to Adobe Experience Platform Data Collection using your AdobeID credentials.
  2. Click the desired tag property.
  3. Go to the Rules tab, then click the desired rule.
  4. Under Actions, click the desired Action or click the ‘+’ icon to add a new action.
  5. Set the Extension drop-down list to Adobe Experience Platform Web SDK and the Action Type to Send event
  6. Click the checkbox Document will unload on the right.

If this box is checked, data is sent to Adobe using the sendBeacon API. It is unchecked by default.

Use the sendBeacon API manually implementing the Web SDK

Set documentUnloading to true when sending an event. If not set, its default value is false.

alloy("sendEvent", {
  "documentUnloading": true,
  "xdm": {}

See Using the sendBeacon API in the Web SDK documentation for more information.

Use Beacon using the Adobe Analytics extension

There is not a dedicated field in the Adobe Analytics extension to use this variable. Use the custom code editor, following AppMeasurement syntax.

s.useBeacon in AppMeasurement and the Analytics extension custom code editor

The s.useBeacon variable is a boolean that determines if AppMeasurement uses the browser’s navigator.sendBeacon() method. Its default value is false. Set this variable to true before calling a tracking function if you want to use the asynchronous nature of navigator.sendBeacon().

s.useBeacon = true;
After a tracking call runs, this variable is reset to false. If your implementation sends multiple image requests in the same page load (such as single-page applications), set this variable to true before each tracking call.