Best way to sync events w/ music?

I'm wondering what the best way to sync events with music is. Normally I just use "compare time" or I constantly add n*dt to a value and use that but it would seem, every now and then and most likely due to load times or something, that the music and events get out of sync. I wait until all audio is pre-loaded before starting the game, though..so hm. Anything else I could be doing?

With audio support as it is, there's probably not much you can do. Perhaps there's something in the Web Audio API, but I'm not sure.

Are you looking for a one-time synced event, or for an event to happen multiple times in time with music?

Hmm. I guess imagine Tom & Jerry and how the music is synced with their movements, just on a MUCH smaller scale.

Say there's a scene when the music smoothly transitions from happy to sad, and something in the game reflects that - or maybe a song is playing through the intro and it only goes to the title screen when the song 'kicks off' - all that has to be perfectly in sync or it will look bad / cause upcoming events to be out of sync as well.

Tracking down the milliseconds and executing the right event(s) based on that seems to be the only thing I can do, and it works pretty well provided there are no lag spikes / slow load times or something...but they are inevitable it seems.

Wouldn't be it cool, if there would be a midi-engine playing midi files and also trigger events based on the midi-file?!?

....just dreaming.....