track
elementkind
src
srclang
label
default
interface HTMLTrackElement : HTMLElement { attribute DOMString kind; attribute DOMString src; attribute DOMString srclang; attribute DOMString label; attribute boolean default; const unsigned short NONE = 0; const unsigned short LOADING = 1; const unsigned short LOADED = 2; const unsigned short ERROR = 3; readonly attribute unsigned short readyState; readonly attribute TextTrack track; };
The track
element allows authors to specify
explicit external timed text tracks for media elements. It
does not represent anything on its own.
The kind
attribute is an enumerated attribute. The following
table lists the keywords defined for this attribute. The keyword
given in the first cell of each row maps to the state given in the
second cell.
Keyword | State | Brief description |
---|---|---|
subtitles |
Subtitles | Transcription or translation of the dialogue, suitable for when the sound is available but not understood (e.g. because the user does not understand the language of the media resource's audio track). Overlaid on the video. |
captions |
Captions | Transcription or translation of the dialogue, sound effects, relevant musical cues, and other relevant audio information, suitable 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). Overlaid on the video; labeled as appropriate for the hard-of-hearing. |
descriptions |
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). Synthesized as audio. |
chapters |
Chapters | Chapter titles, intended to be used for navigating the media resource. Displayed as an interactive (potentially nested) list in the user agent's interface. |
metadata |
Metadata | Tracks intended for use from script. Not displayed by the user agent. |
The attribute may be omitted. The missing value default is the subtitles state.
The src
attribute gives the address
of the text track data. The value must be a valid
non-empty URL potentially surrounded by spaces. This attribute
must be present.
If the element's track
URL identifies a WebVTT
resource, and the element's kind
attribute is not in the metadata state, then the WebVTT
file must be a
WebVTT file using cue text. [WEBVTT]
Furthermore, if the element's track
URL identifies a WebVTT
resource, and the element's kind
attribute is in the chapters state, then the WebVTT
file must be both a
WebVTT file using chapter title text and a
WebVTT file using only nested cues. [WEBVTT]
The srclang
attribute gives the
language of the text track data. The value must be a valid BCP 47
language tag. This attribute must be present if the element's
kind
attribute is in the subtitles state. [BCP47]
The label
attribute gives a
user-readable title for the track. This title is used by user
agents when listing subtitle, caption, and audio description tracks in
their user interface.
The value of the label
attribute, if the attribute is
present, must not be the empty string. Furthermore, there must not
be two track
element children of the same
media element whose kind
attributes are in the same state, whose
srclang
attributes are both missing or
have values that represent the same language, and whose
label
attributes are again both missing or
both have the same value.
The default
attribute, if
specified, indicates 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.
readyState
Returns the text track readiness state, represented by a number from the following list:
NONE
(0)The text track not loaded state.
LOADING
(1)The text track loading state.
LOADED
(2)The text track loaded state.
ERROR
(3)The text track failed to load state.
track
Returns the TextTrack
object corresponding to the
text track of the track
element.
This video has subtitles in several languages:
<video src="brave.webm"> <track kind=subtitles src=brave.en.vtt srclang=en label="English"> <track kind=captions src=brave.en.hoh.vtt srclang=en label="English for the Hard of Hearing"> <track kind=subtitles src=brave.fr.vtt srclang=fr lang=fr label="Français"> <track kind=subtitles src=brave.de.vtt srclang=de lang=de label="Deutsch"> </video>