The visibilitychange event is sent to an XRSession to inform it when it becomes visible or hidden, or when it becomes visible but not currently focused. Upon receiving the event, you can check the value of the session's visibilityState property to determine the new visibility state.

Use the event name in methods like addEventListener(), or set an event handler property.

addEventListener("visibilitychange", (event) => {});

onvisibilitychange = (event) => {};

An XRSessionEvent. Inherits from Event.

In addition to the properties listed below, properties from the parent interface, Event, are available.

session Read only

The XRSession to which the event refers.

Triggered when an XRSession becomes visible or hidden, or when it becomes visible but not currently focused.

When the XRSession receives this event, the visibility state has already been changed.

Upon receiving the event, you can check the value of the session's visibilityState property to determine the new visibility state.

This example demonstrates how to listen for a visibilitychange event on a WebXR session, using addEventListener() to begin listening for the event:

navigator.xr.requestSession("inline").then((xrSession) => {
  xrSession.addEventListener("visibilitychange", (e) => {
    switch (e.session.visibilityState) {
      case "visible":
      case "visible-blurred":
        mySessionVisible(true);
        break;
      case "hidden":
        mySessionVisible(false);
        break;
    }
  });
});

When a visibility state change occurs, the event is received and dispatched to a function mySessionVisible(), with a Boolean parameter indicating whether or not the session is presently being displayed to the user.

You can also create the event handler by assigning it to the XRSession's onvisibilitychange event handler property, like this:

xrSession.onvisibilitychange = (e) => {
  /* event handled here */
};