SpeechRecognition: start event

The start event of the Web Speech API SpeechRecognition object is fired when the speech recognition service has begun listening to incoming audio with intent to recognize grammars associated with the current SpeechRecognition.

You can use the start event in an addEventListener method:

var recognition = new webkitSpeechRecognition() || new SpeechRecognition();

recognition.addEventListener('start', function() {
  console.log('Speech recognition service has started');
});

Or use the onstart event handler property:

recognition.onstart = function() {
  console.log('Speech recognition service has started');
}

• Web Speech API