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This is an experimental technology
Because this technology's specification has not stabilized, check the compatibility table for the proper prefixes to use in various browsers. Also note that the syntax and behavior of an experimental technology is subject to change in future versions of browsers as the spec changes.

The MediaKeySession.expiration read-only property returns 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.


​var expirationTime = mediaKeySessionObj.expiration;


Specification Status Comment
Encrypted Media Extensions
The definition of 'expiration' in that specification.
Working Draft Initial definition

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari (WebKit)
Basic support 42.0 ? ? ? ?
Feature Android Android Webview Firefox Mobile (Gecko) Firefox OS IE Mobile Opera Mobile Safari Mobile Chrome for Android
Basic support Not supported 43.0 ? ? ? ? ? 42.0

Document Tags and Contributors

 Contributors to this page: Sebastianz, meljag, jpmedley
 Last updated by: Sebastianz,