HTML next - HTML5 in Action - page 556

Listing I.15. Listening to the cuechange event
Now when the user clicks the Descriptions button, the descriptions will be updated auto-
matically as the cues change. Grab file index-vtt-5.html to try it for yourself.
Although you've used the API to read the descriptions in this section, a more common use
would be to perform an action at a particular time with the media. If you refer to table I.2 ,
you'll note that the last kind of track is metadata. This can be used for any kind of data you
want to use from within your scripts; for example, you could have a series of cues popu-
lated with data in JSON format.
Before we move on to other things, let's take a look at styling the cues as they appear on
the video.