Detailed answer
Track associates timed text with media, such as captions or subtitles.
WebVTT is a commonly used format. Supply a language and meaningful label so viewers can choose a track. Captions include relevant sound information in addition to dialogue. Test the track with actual playback rather than checking only the markup.
Example
<video controls src="lesson.mp4"><track kind="captions" src="captions-en.vtt" srclang="en" label="English" default></video>
Understanding the behavior
A track can reference timed text such as captions in WebVTT format. The kind, language and label help the browser present the track appropriately. Captions should include meaningful non-speech sounds as well as spoken dialogue.
Practical implementation notes
Enable captions in the player and check their timing against the video. Confirm the track file loads successfully; a correctly written track element cannot repair a missing file or inaccurate caption content.
How to check it
Check the track URL, WebVTT response, language, label, and selected track during playback.
Expected result
The track becomes selectable and captions are synchronized with the media.
Watch out: Captions and translated subtitles serve related but different needs.
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