webkitSpeechRecognition keep listening always without ask for more than one permission

I am using webkitSpeechRecognition to my app, but after some time it stops, and I need that keep listening all the time, how can I do that?.

I have watched examples through internet, but they are old and the most of them have an implementation like this function that starts again

recognition.onend = function(event){
    recognition.start();
}

I use it, but always that I finish to speak I need to give permission in the browser.

I don’t know if by browser politics I need to give permission always that I use my microphone.