Cut audio with javascript

Well, I was able to solve my problem and came back here to share the solution for someone who might need it in the future. Even because I did not find anything similar on the net as incredible as it seems.

VanillaJS

window.onload = function (){
  'use strict';

   var xhr = new XMLHttpRequest();
    xhr.open("GET",'path/da/musica', true);
    xhr.responseType = "arraybuffer";

    xhr.onload = function (e) {
        var blob    = new Blob([xhr.response], {type: "audio/mp3"});
        var newBlob = new Blob([blob.slice(/*Início em bytes*/, /*Fim em bytes*/)],    {type:"audio/mp3"});

        var reader = new FileReader();
            reader.onload = function(){

            var dataURL = reader.result;
            var output = document.getElementById('audio');
            output.src = dataURL;
            output.autoplay = true;
       };

        reader.readAsDataURL(newBlob);

    }

    xhr.send(null);
}

HTML

<audio id="audio"></audio>

Note: I did not use it in the most orthodox way, but it is functional