There’s not currently an event generated for timeline time changes.
The two basic techniques are:
- Use your own timer (via setInterval or requestAnimationFrame) and check the timeline time. Be aware of resource management and making sure to not eat unnecessary CPU.
- Create an animation with a Math Equation timing function and as this is javascript, call out to your own function callback here.
(side note, this was recently done for a different purpose by @MaxZieb in this post and I believe generalized with a timer/callback in this one).