CSS animations provide high resolution timer
TBB supports CSS animations out of the box (even without Javascript). These animations run smoothly and likely result in at least 60Hz resolution.
All kinds of properties can be animated and can be turned into Javascript events (e.g. using change events) to create timers.
CSS animation demo: https://developer.mozilla.org/en-US/docs/Web/CSS/CSS_Animations/Using_CSS_animations