wavesurfer.js + Microphone

var wavesurfer = WaveSurfer.create({
  container     : '#waveform',
  waveColor     : 'black',
  interact      : false,
  cursorWidth   : 0,
  plugins: [
    WaveSurfer.microphone.create()
  ]
});

wavesurfer.microphone.on('deviceReady', function(stream) {
    console.log('Device ready!', stream);
});
wavesurfer.microphone.on('deviceError', function(code) {
    console.warn('Device error: ' + code);
});

// start the microphone
wavesurfer.microphone.start();

// pause rendering
//wavesurfer.microphone.pause();

// resume rendering
//wavesurfer.microphone.play();

// stop visualization and disconnect microphone
//wavesurfer.microphone.stopDevice();

// same as stopDevice() but also clears the wavesurfer canvas
//wavesurfer.microphone.stop();

// destroy the plugin
//wavesurfer.microphone.destroy();