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;
This is a non standard implementation, but it is discussed at W3C as part of the System Application Working Group.
|Web Telephony||Draft||Editor Draft (WIP).|
For obvious reasons, support is primarily expected on mobile browsers.
Supported in Firefox OS 1.0.1