length

length property

Returns the number of tracks in TextTrackList, VideoTrackList, TextTrackCueList, or AudioTrackList objects.

This property is read-only.

HTML5 A vocabulary and associated APIs for HTML and XHTMLInternet Explorer 10

 

Syntax

JavaScript
numTracks = object.length

 

Property values

Type: number

Number of tracks represented by the list object.

Standards information

Remarks

The maximum number of audio tracks a video can contain has not been defined in the World Wide Web Consortium (W3C) specification.

VideoTrackList support not supported in versions before Internet Explorer 11.

Examples

The following example uses the length property to get the number of audioTracks associated with a video object, and then displays the language and enabled status of each.


<!DOCTYPE html >
<html >
  <head>
  <title>AudioTracks example</title>

  </head>
  <body>
    <h1>AudioTrack languages example</h1>
    <video id="video1" src="multi-lang-movie.mp4" controls >HTML5 video not supported </video>
    <br />
    <button id="mybutton">Get language status</button>
    <div id="display"></div>
  
    <script>
      document.getElementById("mybutton").addEventListener("click", function () {
        var oAudioTracks = document.getElementById("video1").audioTracks;
        var display = document.getElementById("display");
        display.innerHTML = "";
        for (var i = 0; i < oAudioTracks.length; i++) {
          display.innerHTML += "Track " + i;
          display.innerHTML += " Language: " + oAudioTracks[i].language;
          display.innerHTML += " is   " + ((oAudioTracks[i].enabled == true) ? "enabled" : "not enabled") + "<br/>";
        }
      },false);    
  </script>
  </body>
</html>


See also

AudioTrackList
TextTrackCueList
TextTrackList
VideoTrackList

 

 

Show:
© 2016 Microsoft