The TextTrack
interface—part of the API for handling WebVTT (text tracks on media presentations)—describes and controls the text track associated with a particular <track>
element.
The TextTrack
interface—part of the API for handling WebVTT (text tracks on media presentations)—describes and controls the text track associated with a particular <track>
element.
This interface also inherits properties from EventTarget
.
TextTrack.activeCues
Read only
A TextTrackCueList
object listing the currently active set of text track cues. Track cues are active if the current playback position of the media is between the cues' start and end times. Thus, for displayed cues such as captions or subtitles, the active cues are currently being displayed.
TextTrack.cues
Read only
A TextTrackCueList
which contains all of the track's cues.
TextTrack.id
Read only
A string which identifies the track, if it has one. If it doesn't have an ID, then this value is an empty string (""
). If the TextTrack
is associated with a <track>
element, then the track's ID matches the element's ID.
TextTrack.inBandMetadataTrackDispatchType
Read only
Returns a string which indicates the track's in-band metadata track dispatch type.
TextTrack.kind
Read only
Returns a string indicating what kind of text track the TextTrack
describes. It must be one of the permitted values.
TextTrack.label
Read only
A human-readable string which contains the text track's label, if one is present; otherwise, this is an empty string (""
), in which case a custom label may need to be generated by your code using other attributes of the track, if the track's label needs to be exposed to the user.
TextTrack.language
Read only
A string which specifies the text language in which the text track's contents is written. The value must adhere to the format specified in RFC 5646: Tags for Identifying Languages (also known as BCP 47), just like the HTML lang
attribute. For example, this can be "en-US"
for United States English or "pt-BR"
for Brazilian Portuguese.
TextTrack.mode
A string specifying the track's current mode, which must be one of the permitted values. Changing this property's value changes the track's current mode to match. The default is disabled
, unless the <track>
element's default
boolean attribute is set to true
— in which case the default mode is showing
.
This interface also inherits methods from EventTarget
.
Note: The TextTrackCue
interface is an abstract class used as the parent for other cue interfaces such as VTTCue
. Therefore, when adding or removing a cue you will be passing in one of the cue types that inherit from TextTrackCue
.
TextTrack.addCue()
Adds a cue (specified as a TextTrackCue
object) to the track's list of cues.
TextTrack.removeCue()
Removes a cue (specified as a TextTrackCue
object) from the track's list of cues.
cuechange
Fired when cues are entered and exited. A given text cue appears when the cue is entered and disappears when the cue is exited. Also available via the oncuechange
property.
The following example adds a new TextTrack
to a video, then sets it to display using TextTrack.mode
.
js
let video = document.querySelector("video"); let track = video.addTextTrack("captions", "Captions", "en"); track.mode = "showing";
Specification |
---|
HTML Standard # texttrack |
Desktop | Mobile | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Chrome | Edge | Firefox | Internet Explorer | Opera | Safari | WebView Android | Chrome Android | Firefox for Android | Opera Android | Safari on IOS | Samsung Internet | |
TextTrack |
23 | 12 | 31Firefox versions before Firefox 50 didn't display captions when playing media without one or more video tracks being played. |
10 | ≤12.1 | 6 | 4.4 | 25 | 31 | ≤12.1 | 7 | 1.5 |
activeCues |
23 | 12 | 31Starting in Firefox 69, cues are no longer incorrectly loaded when theTextTrack 's mode is disabled ; if that's the case, the returned list is empty. |
10 | ≤12.1 | 6 | 4.4 | 25 | 31 | ≤12.1 | 7 | 1.5 |
addCue |
23 | 12 | 31 | 10 | ≤12.1 | 6 | 4.4 | 25 | 31 | ≤12.1 | 7 | 1.5 |
cuechange_event |
23 | 12 | 31 | 10 | ≤12.1 | 6 | 4.4 | 25 | 31 | ≤12.1 | 7 | 1.5 |
cues |
23 | 12 | 31Starting in Firefox 69, cues are no longer incorrectly loaded when theTextTrack 's mode is disabled ; if that's the case, the returned list is empty. |
10 | ≤12.1 | 6 | 4.4 | 25 | 31 | ≤12.1 | 7 | 1.5 |
id |
33 | 18 | 31 | No | 20 | 8 | 4.4.3 | 33 | 31 | 20 | 8 | 2.0 |
inBandMetadataTrackDispatchType |
No | 12–79 | 31 | No | No | 8 | No | No | 31 | No | 8 | No |
kind |
23 | 12 | 31 | 10 | ≤12.1 | 6 | 4.4 | 25 | 31 | ≤12.1 | 7 | 1.5 |
label |
23 | 12 | 31 | 10 | ≤12.1 | 6 | 4.4 | 25 | 31 | ≤12.1 | 7 | 1.5 |
language |
23 | 12 | 31 | 10 | ≤12.1 | 6 | 4.4 | 25 | 31 | ≤12.1 | 7 | 1.5 |
mode |
23 | 12 | 31Before Firefox 52, using JavaScript to change the mode of a text track that's part of a media element would send one change event to the element's textTracks TextTrackList for each change, even if multiple changes are made in a single pass through the Firefox event loop. Starting in Firefox 52, these changes are reflected by a single event. |
10 | ≤12.1 | 6 | 4.4 | 25 | 31 | ≤12.1 | 7 | 1.5 |
removeCue |
23 | 12 | 31 | 10 | ≤12.1 | 6 | 4.4 | 25 | 31 | ≤12.1 | 7 | 1.5 |
sourceBuffer |
No | No | No | No | No | 8 | No | No | No | No | 13Exposed in Mobile Safari on iPad but not on iPhone. |
No |
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https://developer.mozilla.org/en-US/docs/Web/API/TextTrack