setTimeout(), setInterval(), and requestAnimationFrame()

requestAnimationFrame(function update(timestamp) {
  // animation code
  if (shouldContinue) requestAnimationFrame(update);
});

Current system time
Time since page load
Time for smooth animation calculation
The timestamp parameter provides: 1) DOMHighResTimeStamp for precise animation timing, 2) Milliseconds since page load with microsecond precision, 3) Used for calculating smooth animation progress, 4) Enables frame-rate independent animations, 5) More accurate than Date.now() for animations, 6) Essential for implementing proper animation timing.
Animation duration