VRDisplayEvent: reason property

Deprecated: This feature is no longer recommended. Though some browsers might still support it, it may have already been removed from the relevant web standards, may be in the process of being dropped, or may only be kept for compatibility purposes. Avoid using it, and update existing code if possible; see the compatibility table at the bottom of this page to guide your decision. Be aware that this feature may cease to work at any time.

Non-standard: This feature is non-standard and is not on a standards track. Do not use it on production sites facing the Web: it will not work for every user. There may also be large incompatibilities between implementations and the behavior may change in the future.

The reason read-only property of the VRDisplayEvent interface returns a human-readable reason why the event was fired.

Note: This property was part of the old WebVR API. It has been superseded by the WebXR Device API.

Value

A string representing the reason why the event was fired. The available reasons are defined in the VRDisplayEventReason enum, and are as follows:

  • mounted — The VRDisplay has detected that the user has put it on (or it has been otherwise activated).
  • navigation — The page has been navigated to from a context that allows this page to begin presenting immediately, such as from another site that was already in VR presentation mode.
  • requested — The user agent has requested that VR presentation mode be started. This allows user agents to include a consistent UI to enter VR across different sites.
  • unmounted — The VRDisplay has detected that the user has taken it off (or it has been otherwise slept/put on standby).

Examples

js

window.addEventListener("vrdisplaypresentchange", (e) => {
  console.log(
    `Display ${e.display.displayId} presentation has changed. Reason given: ${e.reason}.`,
  );
});

Specifications

This property was part of the old WebVR API that has been superseded by the WebXR Device API. It is no longer on track to becoming a standard.

Until all browsers have implemented the new WebXR APIs, it is recommended to rely on frameworks, like A-Frame, Babylon.js, or Three.js, or a polyfill, to develop WebXR applications that will work across all browsers [1].

Browser compatibility

BCD tables only load in the browser

See also