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HTML 5 <track> Tag

The HTML 5 <track> tag is used to specify external timed text tracks for media elements (i.e. the <video> element and the <audio> element). The text tracks specified with the <track> tag could include subtitles, captions, descriptions, chapters, and metadata.

Note that the <track> element was first introduced into HTML5 in late 2010 and therefore, browser support for this element may be limited for some time.

Example

This example demonstrates usage of the <track> tag.

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The above example uses a file called countdown_en.vtt to present subtitles.

Here are the contents of the countdown_en.vtt file:

The file simply specifies which text to display at which parts of the video. To add more subtitles, simply add more text and specify the appropriate points in the video that they should be displayed.

Attributes

HTML tags can contain one or more attributes. Attributes are added to a tag to provide the browser with more information about how the tag should appear or behave. Attributes consist of a name and a value separated by an equals (=) sign, with the value surrounded by double quotes. Here's an example, style="color:black;".

There are 3 kinds of attributes that you can add to your HTML tags: Element-specific, global, and event handler content attributes.

The attributes that you can add to this tag are listed below.

Element-Specific Attributes

The following table shows the attributes that are specific to this tag/element.

AttributeDescription
kindSpecifies the kind of text track. This attribute is an enumerated attribute.

The possible values for the "kind" attribute are:

ValueDescription
subtitlesTranscription or translation of the dialogue. This can be useful for when the sound is in a different language to what the user can understand. Any subtitles are overlaid on the video. This is the default value.
captionsTranscription or translation of the dialogue, sound effects, relevant musical cues, and other relevant audio information. This can be useful for when sound is unavailable or not clearly audible (e.g. because it is muted, drowned-out by ambient noise, or because the user is deaf). Any captions are overlaid on the video; labeled as appropriate for the hard-of-hearing.
descriptionsTextual descriptions of the video component of the media resource, intended for audio synthesis when the visual component is obscured, unavailable, or not usable (e.g. because the user is interacting with the application without a screen while driving, or because the user is blind). Any descriptions are synthesized as audio.
chaptersChapter titles, intended to be used for navigating the media resource. Any chapters are displayed as an interactive list in the user agent/browser's interface.
metadataTracks intended for use from script. Not displayed by the user agent.
srcSpecifies the URL of the text track data. Required attribute.
srclangSpecifies the language of the text track. The value must be a valid BCP 47 language tag. This attribute is required if the element's kind attribute is "subtitles".
labelProvides a user-readable title for the track.
defaultSpecifies that the track is to be enabled if the user's preferences do not indicate that another track would be more appropriate. There must not be more than one track element with the same parent node with the default attribute specified.

Global Attributes

The following attributes are standard across all HTML 5 tags.

For a full explanation of these attributes, see HTML 5 global attributes.

Event Handler Content Attributes

Event handler content attributes enable you to invoke a script from within your HTML. The script is invoked when a certain "event" occurs. Each event handler content attribute deals with a different event.

Here are the standard HTML 5 event handler content attributes.

For a full explanation of these attributes, see HTML 5 event handler content attributes.

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