The MediaKeySession interface of the EncryptedMediaExtensions API represents a context for message exchange with a content decryption module (CDM).


MediaKeySession.closed 只读
Returns a Promise signaling when a MediaKeySession closes. This promise can only be fulfilled and is never rejected. Closing a session means that licenses and keys associated with it are no longer valid for decrypting media data. 
MediaKeySession.expiration 只读
The time after which the keys in the current session can no longer be used to decrypt media data, or NaN if no such time exists. This value is determined by the CDM and measured in milliseconds since January 1, 1970, UTC. This value may change during a session lifetime, such as when an action triggers the start of a window.
MediaKeySession.keyStatuses 只读
Contains a reference to a read-only MediaKeyStatusMap of the current session's keys and their statuses.
MediaKeySession.sessionId 只读
Contains a unique string generated by the CDM for the current media object and its associated keys or licenses.

Event handlers

Sets the EventHandler called when there has been a change in the keys in a session or their statuses.
Sets the EventHandler called when the content decryption module has generated a message for the session.



Returns a Promise after notifying the current media session is no longer needed and that the CDM should release any resources associated with this object and close it.

Returns a Promise after generating a media request based on initialization data.
Returns a Promise that resolves to a boolean value after loading data for a specified session object. 
Returns a Promise after removing any session data associated with the current object.
Returns a Promise after loading messages and licenses to the CDM.


// TBD


Specification Status Comment
Encrypted Media Extensions
Recommendation Initial definition.

Browser compatibility

We're converting our compatibility data into a machine-readable JSON format. This compatibility table still uses the old format, because we haven't yet converted the data it contains. Find out how you can help!

Feature Chrome Edge Firefox (Gecko) Internet Explorer Opera Safari (WebKit)
Basic support 42.0 (Yes) ? ? (Yes) ?
onkeystatuseschange and onmessage 55.0 ? ? ? 42 ?
Feature Android Android Webview Edge Firefox Mobile (Gecko) Firefox OS IE Mobile Opera Mobile Safari Mobile Chrome for Android
Basic support 未实现 43.0 (Yes) ? ? ? (Yes) ? 42.0
onkeystatuseschange and onmessage 未实现 55.0 ? ? ? ? 42 ? 55.0


 此页面的贡献者: Sheppy
 最后编辑者: Sheppy,