In the Web VR API there was an event listener for entering/exiting VR display;
window.addEventListener('vrdisplaypresentchange', function() {
//do something
}
Is there an equivalent for the Web XR API?
Not really sure why it was downvoted (twice!).
The WebXR specs define a few events:
https://www.w3.org/TR/webxr/#event-types
As you can see there, there is a visibilitychange
event (https://www.w3.org/TR/webxr/#eventdef-xrsession-visibilitychange) that might be helpful, but it really depends on what you are trying to achieve.