files/en-us/web/api/audiotracklist/length/index.md
{{APIRef("HTML DOM")}}
The read-only {{domxref("AudioTrackList")}}
property length returns the number of entries in the
AudioTrackList, each of which is an {{domxref("AudioTrack")}}
representing one audio track in the media element. A value of 0 indicates that
there are no audio tracks in the media.
A number indicating how many audio tracks are included in the
AudioTrackList. Each track can be accessed by treating the
AudioTrackList as an array of objects of type {{domxref("AudioTrack")}}.
This snippet gets the number of audio tracks in the first {{HTMLElement("video")}} element found in the {{Glossary("DOM")}} by {{domxref("Document.querySelector", "querySelector()")}}.
const videoElem = document.querySelector("video");
let numAudioTracks = 0;
if (videoElem.audioTracks) {
numAudioTracks = videoElem.audioTracks.length;
}
Note that this sample checks to be sure {{domxref("HTMLMediaElement.audioTracks")}} is defined, to avoid failing on browsers without support for {{domxref("AudioTrack")}}.
{{Specifications}}
{{Compat}}