The enter event fires when a cue becomes active. In the case of subtitles or a caption this is when it displays over the media.

Use the event name in methods like addEventListener(), or set an event handler property.

addEventListener("enter", (event) => {});

onenter = (event) => {};

A generic Event with no added properties.

In the following example, cue1 prints to the console when it is the active cue.

cue1.addEventListener("enter", (event) => {
  console.log("Cue 1 has displayed");
});