HTML <track> Tag

The HTML <track> tag is used to specify external timed text tracks for media elements.

HTML5 defines two elements as "media elements": the <video> element and the <audio> element).

There are 5 kinds of text tracks: subtitles, captions, descriptions, chapters, and metadata.

Syntax

The <track> tag is written as <track src=""> (no end tag). The src attribute is a required attribute that provides the URL of the text track.

You can use the (optional) type attribute to specify the kind of text track. The srclang attribute must be present if the kind attribute is in the subtitles state. Note that, if you omit the type attribute, it defaults to subtitles, so you will need to provide a srclang attribute in this case.

You can also include the (optional) label attribute to provide a user-visible label.

The <track> tag must be nested inside a media element (i.e. either <video> or <audio>).

Like this:

Example

In this example, the <track> element is used to provide subtitles in English.

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.

Multiple `<track>` Tags

You can include multiple <track> tags if required. For example, if you have subtitles in many languages, you could provide a different <track> tag for each language.

Like this:

Attributes

Attributes can be added to an HTML element to provide more information about how the element should appear or behave.

The <track> element accepts the following attributes.

Attribute Description

kind

Specifies the kind of text track. This attribute is an enumerated attribute.

The possible values for the "kind" attribute are:

Value	Description
`subtitles`	Transcription 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.
`captions`	Transcription 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.
`descriptions`	Textual 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.
`chapters`	Chapter 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.
`metadata`	Tracks intended for use from script. Not displayed by the user agent.

src Specifies the URL of the text track data. Required attribute.

srclang Specifies 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".

label Provides a user-readable title for the track.

default Specifies 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 elements. Therefore, you can use these attributes with the <track> tag , as well as with all other HTML tags.

accesskey
autocapitalize
class
contenteditable
data-*
dir
draggable
hidden
id
inputmode
is
itemid
itemprop
itemref
itemscope
itemtype
lang
part
slot
spellcheck
style
tabindex
title
translate

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

Event Handlers

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.

onabort
onauxclick
onblur
oncancel
oncanplay
oncanplaythrough
onchange
onclick
onclose
oncontextmenu
oncopy
oncuechange
oncut
ondblclick
ondrag
ondragend
ondragenter
ondragexit
ondragleave
ondragover
ondragstart
ondrop
ondurationchange
onemptied
onended
onerror
onfocus
onformdata
oninput
oninvalid
onkeydown
onkeypress
onkeyup
onlanguagechange
onload
onloadeddata
onloadedmetadata
onloadstart
onmousedown
onmouseenter
onmouseleave
onmousemove
onmouseout
onmouseover
onmouseup
onpaste
onpause
onplay
onplaying
onprogress
onratechange
onreset
onresize
onscroll
onsecuritypolicyviolation
onseeked
onseeking
onselect
onslotchange
onstalled
onsubmit
onsuspend
ontimeupdate
ontoggle
onvolumechange
onwaiting
onwheel

Most event handler content attributes can be used on all HTML elements, but some event handlers have specific rules around when they can be used and which elements they are applicable to.

For more detail, see HTML event handler content attributes.