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VideoTrackList: length property

files/en-us/web/api/videotracklist/length/index.md

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{{APIRef("HTML DOM")}}

The read-only {{domxref("VideoTrackList")}} property length returns the number of entries in the VideoTrackList, each of which is a {{domxref("VideoTrack")}} representing one video track in the media element.

A value of 0 indicates that there are no video tracks in the media.

Value

A number indicating how many video tracks are included in the VideoTrackList. Each track can be accessed by treating the VideoTrackList as an array of objects of type {{domxref("VideoTrack")}}.

Examples

This snippet gets the number of video tracks in the first {{HTMLElement("video")}} element found in the {{Glossary("DOM")}} by {{domxref("Document.querySelector", "querySelector()")}}.

js
const videoElem = document.querySelector("video");
let numVideoTracks = 0;

if (videoElem.videoTracks) {
  numVideoTracks = videoElem.videoTracks.length;
}

Note that this sample checks to be sure {{domxref("HTMLMediaElement.videoTracks")}} is defined, to avoid failing on browsers without support for {{domxref("VideoTrack")}}.

Specifications

{{Specifications}}

Browser compatibility

{{Compat}}