The currentTime read-only property of the Web Animations API's AnimationTimeline interface returns the timeline's current time in milliseconds, or null if the timeline is inactive.

A number representing the timeline's current time in milliseconds, or null if the timeline is inactive.

To offer protection against timing attacks and fingerprinting, the precision of animationTimeline.currentTime might get rounded depending on browser settings. In Firefox, the privacy.reduceTimerPrecision preference is enabled by default and defaults to 20us in Firefox 59; in 60 it will be 2ms.

// reduced time precision (2ms) in Firefox 60
animationTimeline.currentTime;
// 23.404
// 24.192
// 25.514
// …

// reduced time precision with `privacy.resistFingerprinting` enabled
animationTimeline.currentTime;
// 49.8
// 50.6
// 51.7
// …

In Firefox, you can also enable privacy.resistFingerprinting; the precision will be 100ms or the value of privacy.resistFingerprinting.reduceTimerPrecision.microseconds, whichever is larger.

• Web Animations API
• AnimationTimeline
• DocumentTimeline inherits this property
• Document.timeline returns a timeline object which inherits this property