Reset Audio file

I am make a music visualizer. When the user decides to load a new song, the current song that is playing should stop, and the new song should play.

here is my code for the audio part:

  var tmp = document.getElementById("mainsvg");
  var stream,newaudio,analyser, width = tmp.clientWidth,dx, dy,
  height = tmp.clientHeight,audioSRC;
  var audioCTX = new (window.AudioContext || window.webkitAudioContest)();
  var audio = document.getElementById("audiofile");
  if (audio){
   audio.value="";
  }
 audio.addEventListener("change", function(event){
    stream = URL.createObjectURL(event.target.files[0]);
    newaudio = new Audio();
    newaudio.src=stream;
    newaudio.addEventListener('canplay', function () {
    audioSRC = audioCTX.createMediaElementSource(newaudio);
    analyser = audioCTX.createAnalyser();
    audioSRC.connect(analyser);
    audioSRC.connect(audioCTX.destination);
    newaudio.play();
    callfirst();
    });

  });

however, when i run this code. The old song still plays along with the new selected song. How do i fix this?