VRDisplayEvent.reason

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

Browser compatibility

See also

• WebVR API homepage
• MozVr.com — demos, downloads, and other resources from the Mozilla VR team.