VRPositionState.timeStamp

The timeStamp read-only property of the VRPositionState interface returns the current time stamp of the system — a monotonically increasing value representing the time since the current app was started.

This property is useful for determining if position data has been updated, and what order updates have occured in.

Syntax

var myTimeStamp = VRPositionState.timeStamp;

Value

A double, representing the timestamp, in seconds, defined using the same base as Performance.now.

Examples

The following example is taken from our positionsensorvrdevice demo, which uses the WebVR API to update the view of a simple 2D canvas scene on each frame of a requestAnimationFrame loop. The main function that updates the rendering according to movement of the head mounted display is setView():

function setView() {
  var posState = gPositionSensor.getState();
  
    ...

  timePara.textContent = 'Timestamp: ' + Math.floor(posState.timeStamp);
}

Here we are grabbing a VRPositionState object using getState() and storing it in posState. From this object we grab a wide variety of data and use it for a number of purposes, but here only the immediately relevant lines are shown — on each frame, we display the updated timestamp (rounded down to the nearest integer) in a paragraph inside the UI.

Specifications

Browser compatibility

• [1] The support in Chrome is currently experimental. To find information on Chrome's WebVR implementation status including supporting builds, check out Bringing VR to Chrome by Brandon Jones.
• [2] The support for this feature is currently disabled by default in Firefox. To enable WebVR support in Firefox Nightly/Developer Edition, you can go to about:config and enable the dom.vr* prefs. A better option however is to install the WebVR Enabler Add-on, which does this for you and sets up other necessary parts of the environment.
• [3] The dom.vr* prefs are enabled by default at this point, in Nightly/Aurora editions.

See also

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