js

let video = document.querySelector("video");
let track = video.addTextTrack("captions", "Captions", "en");
track.mode = "showing";

let cue1 = new VTTCue(0, 0.9, "Hildy!");
cue1.text = "new cue value";
console.log(cue1.text); // 'new cue value';

track.addCue(cue1);