Javascript - How to detect when user enters VR mode?

Question

Is there any JavaScript event triggered when the user enters VR mode while viewing the VR scene on a webpage?

Or is there any function which returns whether the user is viewing the webpage in VR mode or not?

Answer 1

Use the enter-vr and exit-vr events:

https://aframe.io/docs/0.5.0/core/scene.html#events

document.querySelector('a-scene').addEventListener('enter-vr', function () {
   console.log("ENTERED VR");
});