The following snippet is taken from our AudioContext states demo (see it running live.) The onstatechange hander is used to log the current state to the console every time it changes.

API AudioContext onstatechange Property Reference Référence Web Audio API

An EventListener property called whenever an event of type statechange is fired; it is basically fired anytime the ServiceWorker.state changes.

API onstatechange Property Reference Référence Service Workers ServiceWorker

API B2G Certified DOM DOM Reference Firefox OS Mobile Non-standard onstatechange Property Reference Référence Telephony TelephonyCall WebAPI

API B2G Certified DOM DOM Reference Firefox OS Mobile Non-standard onstatechange Property Reference Telephony TelephonyCallGroup