Secure context: This feature is available only in secure contexts (HTTPS), in some or all supporting browsers.
The deviceId read-only property of the MediaDeviceInfo interface returns a string that is an identifier for the represented device and is persisted across sessions.
It is un-guessable by other applications, and unique to the origin of the calling application. It is reset when the user clears cookies. For private browsing, a different identifier is used that is not persisted across sessions.
A string.