VRDisplayEvent: reason property
Deprecated
Avoid using this feature in new projects. Development of the WebVR API halted in favor of WebXR. This feature may be a candidate for removal from web standards or browsers.
Consider using the following features instead: WebXR.
Non-standard: This feature is not standardized. We do not recommend using non-standard features in production, as they have limited browser support, and may change or be removed. However, they can be a suitable alternative in specific cases where no standard option exists.
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 It has been superseded by the WebXR Device API.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— TheVRDisplayhas 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— TheVRDisplayhas detected that the user has taken it off (or it has been otherwise slept/put on standby).
Examples
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This property was part of the old WebVR API that has been superseded by the WebXR Device API.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. Read Meta's Porting from WebVR to WebXR guide for more information.