This API is available on Firefox OS for internal applications only.


A reference to a function to be called to handle the Telephony API's busy event. This event occurs when the call receives a busy signal from the phone network. The event handler is called with a CallEvent as its only parameter.


instanceOfTelephonyCall.onbusy = funcRef;

Where funcRef is a function to be called when the busy event occurs. These events are of type CallEvent.


This is a non standard implementation, but it is discussed at W3C as part of the System Application Working Group.

Specification Status Comment
Web Telephony Draft Editor Draft (WIP).

Browser compatibility

For obvious reasons, support is primarily expected on mobile browsers.

Supported in Firefox OS 1.0.1

See also