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.

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


var myReason = vrDisplayEventInstance.reason;


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).


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


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

Browser compatibility

BCD tables only load in the browser

See also