The read-only xr property provided by the Navigator interface returns an XRSystem object which can be used to access the WebXR Device API.

The XRSystem object used to interface with the WebXR Device API in the current context. This can be used to present augmented and/or virtual reality imagery to the user.

Each Window has its own instance of Navigator, which can be accessed as window.navigator or as navigator. At the same time, a new XRSystem instance is also created and attached to the navigator instance as navigator.xr. If the xr property exists, you can use it to access the WebXR Device API.

To determine if WebXR is available, you can do something like this:

if ("xr" in window.navigator) {
  /* WebXR can be used! */
} else {
  /* WebXR isn't available */
}

• WebGL API: 2D and 3D accelerated graphics for the web
• Canvas API: 2D graphics API