The inBandMetadataTrackDispatchType read-only property of the TextTrack interface returns the text track's in-band metadata dispatch type of the text track represented by the TextTrack object.

An in-band metadata dispatch type is a string extracted from a media resource specifically for in-band metadata tracks. An example of a media resource that might have such tracks is a TV station streaming a broadcast on the web. Text Tracks may be used to include metadata for ad targeting, additional information such as recipe data during a cooking show, or trivia game data during a game show.

The value of this attribute could be used to attach these tracks to dedicated script modules as they are loaded.

A string containing the inBandMetadataTrackDispatchType, or an empty string.

In the following example the value of inBandMetadataTrackDispatchType is printed to the console.

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