MediaSessionActionDetails

The Media Session API'MediaSessionActionDetails dictionary is the type used by the sole input parameter into the callback which is executed when a media session action occurs. It specifies the type of action which needs to be performed as well as the data needed to perform the action.

Properties

action
A Media Session action type string taken from the MediaSessionAction enumerated type, indicating which type of action needs to be performed. See Media action types below for possible values.
fastSeek Optional
An seekto action may optionally include this property, which is a Boolean value indicating whether or not to perform a "fast" seek. A "fast" seek is a seek being performed in a rapid sequence, such as when fast-forwarding or reversing through the media, rapidly skipping through it. This property can be used to indicate that you should use the shortest possible method to seek the media. fastSeek is not included on the final action in the seek sequence in this situation.
seekOffset Optional
If the action is either seekforward or seekbackward and this property is present, it is a floating point value which indicates the number of seconds to move the play position forward or backward. If this property isn't present, those actions should choose a reasonable default distance to skip forward or backward (such as 7 or 10 seconds).
seekTime Optional
If the action is seekto, this property must be present and must be a floating-point value indicating the absolute time within the media to move the playback position to, where 0 indicates the beginning of the media. This property is not present for other action types.

Media action types

A media session action's type is specified using a string from the MediaSessionAction enumerated type.

Values

Each of the actions is a common media session control request. Implement support for each of these in order to allow that type of action to be performed. The following strings identify the currently available types of media session action:

nexttrack
Advances playback to the next track.
pause
Pauses playback of the media.
play
Begins (or resumes) playback of the media.
previoustrack
Moves back to the previous track.
seekbackward
Seeks backward through the media from the current position. The MediaSessionActionDetails property seekOffset specifies the amount of time to seek backward.
seekforward
Seeks forward from the current position through the media. The MediaSessionActionDetails property seekOffset specifies the amount of time to seek forward.
seekto
Moves the playback position to the specified time within the media. The time to which to seek is specified in the MediaSessionActionDetails property seekTime. If you intend to perform multiple seekto operations in rapid succession, you can also specify the MediaSessionActionDetails property fastSeek property with a value of true. This lets the browser know it can take steps to optimize repeated operations, and is likely to result in improved performance.
skipad
Skips past the currently playing advertisement or commercial. This action may or may not be available, depending on the platform and user agent, or may be disabled due to subscription level or other circumstances.
stop
Halts playback entirely.

Examples

Adding action handlers

This example implements seek forward and backward actions for an audio player by setting up the seekforward and seekbackward action handlers.

let skipTime = 10; // Time to skip in seconds

navigator.mediaSession.setActionHandler('seekforward', details => {
 // User clicked "Seek Forward" media notification icon.
 audio.currentTime = Math.min(audio.currentTime + skipTime,  
               audio.duration);
});

navigator.mediaSession.setActionHandler('seekbackward', details => {
 // User clicked "Seek Backward" media notification icon.
 audio.currentTime = Math.max(audio.currentTime - skipTime, 0);
});

In this case, both the seekforward and seekbackward handlers are using a fixed distance, ignoring the time specified by the MediaSessionActionDetails passed into the handler.

Supporting multiple actions in one handler function

You can also, if you prefer, use a single function to handle multiple action types, by checking the value of the MediaSessionActionDetails object's action property:

let skipTime = 7;

navigator.mediaSession.setActionHandler("seekforward", handleSeek);
navigator.mediaSession.setActionHandler("seekbackward", handleSeek);

function handleSeek(details) {
  switch(details.action) {
    case "seekforward":
      audio.currentTime = Math.min(audio.currentTime + skipTime,
              audio.duration);
      break;
    case "seekbackward":
      audio.currentTime = Math.max(audio.currentTime - skipTime, 0);
      break;
  }
}

Here, the handleSeek() function handles both seekbackward and seekforward actions.

Using data provided by MediaSessionActionDetails

In this example, instead of seeking a specified distance, the seekforward and seekbackward handlers use the time specified in the MediaSessionActionDetails object's seekOffset property.

navigator.mediaSession.setActionHandler("seekforward", handleSeek);
navigator.mediaSession.setActionHandler("seekbackward", handleSeek);

function handleSeek(details) {
  switch(details.action) {
    case "seekforward":
      audio.currentTime = Math.min(audio.currentTime + details.seekOffset,
                                   audio.duration);
      break;
    case "seekbackward":
      audio.currentTime = Math.max(audio.currentTime - details.seekOffset, 0);
      break;
  }
});

Specifications

Specification Status Comment
Media Session Standard
The definition of 'MediaSessionActionDetails' in that specification.
Draft Initial definition.

Browser compatibility

Update compatibility data on GitHub
DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
MediaSessionActionDetails
Experimental
Chrome Full support 73Edge Full support ≤79Firefox Full support 71
Disabled
Full support 71
Disabled
Disabled From version 71: this feature is behind the dom.media.mediasession.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.
IE ? Opera No support NoSafari ? WebView Android No support NoChrome Android Full support 57Firefox Android No support NoOpera Android No support NoSafari iOS ? Samsung Internet Android Full support 7.0
action
Experimental
Chrome Full support 73Edge Full support ≤79Firefox Full support 71
Disabled
Full support 71
Disabled
Disabled From version 71: this feature is behind the dom.media.mediasession.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.
IE ? Opera No support NoSafari ? WebView Android No support NoChrome Android Full support 57Firefox Android No support NoOpera Android No support NoSafari iOS ? Samsung Internet Android Full support 7.0
fastSeek
Experimental
Chrome Full support 73Edge Full support ≤79Firefox No support NoIE ? Opera No support NoSafari ? WebView Android No support NoChrome Android Full support 57Firefox Android No support NoOpera Android No support NoSafari iOS ? Samsung Internet Android Full support 7.0
seekOffset
Experimental
Chrome Full support 73Edge Full support ≤79Firefox Full support 76
Disabled
Full support 76
Disabled
Disabled From version 76: this feature is behind the dom.media.mediasession.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.
IE ? Opera No support NoSafari ? WebView Android No support NoChrome Android Full support 57Firefox Android No support NoOpera Android No support NoSafari iOS ? Samsung Internet Android Full support 7.0
seekTime
Experimental
Chrome Full support 73Edge Full support ≤79Firefox No support NoIE ? Opera No support NoSafari ? WebView Android No support NoChrome Android Full support 57Firefox Android No support NoOpera Android No support NoSafari iOS ? Samsung Internet Android Full support 7.0

Legend

Full support  
Full support
No support  
No support
Compatibility unknown  
Compatibility unknown
Experimental. Expect behavior to change in the future.
Experimental. Expect behavior to change in the future.
User must explicitly enable this feature.
User must explicitly enable this feature.