This is an experimental technology
Check the Browser compatibility table carefully before using this in production.
The reason read-only property of the VRDisplayEvent interface returns a human-readable reason why the event was fired.
Syntax
var myReason = vrDisplayEventInstance.reason;
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 diferent sites.unmounted— TheVRDisplayhas detected that the user has taken it off (or it has been otherwise slept/put on standby).
Examples
window.addEventListener('vrdisplaypresentchange', function(e) {
console.log('Display ' + e.display.displayId + ' presentation has changed. Reason given: ' + e.reason + '.');
})
Specifications
| Specification | Status | Comment |
|---|---|---|
| WebVR 1.1 The definition of 'reason' in that specification. |
Draft | Initial definition |
Browser compatibility
| Feature | Chrome | Edge | Firefox | Internet Explorer | Opera | Safari |
|---|---|---|---|---|---|---|
| Basic support | No | 15 | 555 606 | No | ? | ? |
| Feature | Android webview | Chrome for Android | Edge mobile | Firefox for Android | Opera Android | iOS Safari | Samsung Internet |
|---|---|---|---|---|---|---|---|
| Basic support | No | 561 2 3 4 | ? | ? | ? | ? | 6.0 |
1. Only works in an experimental version of Chrome. (Other builds won't return any devices when Navigator.getVRDisplays() is invoked.)
2. Daydream View supported in Chrome 56.
3. Google Cardboard supported in Chrome 57.
4. From version 56: this feature is behind the WebVR preference. To change preferences in Chrome, visit chrome://flags.
5. Windows support was enabled in Firefox 55.
6. macOS support was enabled in Firefox 60.
See also
- WebVR API homepage
- MozVr.com — demos, downloads, and other resources from the Mozilla VR team.