Web/API/VRDisplayEvent/reason

This is an experimental technologyCheck 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 — 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

window.addEventListener('vrdisplaypresentchange', function(e) {
  console.log('Display ' + e.display.displayId + ' presentation has changed. Reason given: ' + e.reason + '.');
})

Specifications

Specification	Status	Comment
WebVR 1.1The definition of 'reason' in that specification.	Draft	Initial definition

Browser compatibility

Update compatibility data on GitHub

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
`reason` Experimental'Deprecated'	Chrome No support No	Edge No support 15 — 79	Firefox Full support 55 Notes' Full support 55 Notes' Notes' Windows support was enabled in Firefox 55. Full support 64 Notes' Notes' macOS support was enabled in Firefox 64.	IE No support No	Opera ?	Safari No support No	WebView Android No support No	Chrome Android No support 56 — 80 Notes' Disabled' No support 56 — 80 Notes' Disabled' Notes' Only works in an experimental version of Chrome. (Other builds won't return any devices when `Navigator.getVRDisplays()` is invoked.) Notes' Daydream View supported in Chrome 56. Notes' Google Cardboard supported in Chrome 57. Disabled' From version 56 until version 80 (exclusive): this feature is behind the `WebVR` preference. To change preferences in Chrome, visit chrome://flags.	Firefox Android Full support 55	Opera Android ?	Safari iOS ?	Samsung Internet Android Full support 6.0 Notes' Full support 6.0 Notes' Notes' Google Cardboard supported in Samsung Internet 7.0.

Legend

Full support: Full support
No support: No support
Compatibility unknown: Compatibility unknown
Experimental. Expect behavior to change in the future.': Experimental. Expect behavior to change in the future.
Deprecated. Not for use in new websites.': Deprecated. Not for use in new websites.
See implementation notes.': See implementation notes.
User must explicitly enable this feature.': User must explicitly enable this feature.