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  <button id="boton">&#9655;</button>


                html,body{height:100vh; background:#d9d9d9;}
#boton{display:block; margin:0 auto; margin-top:calc(50vh - 2em); }


                //Creamos un nuevo AudioContext.
// Safary y Opera todavía necesitan el prefijo webkit
var audioCtx = new (window.AudioContext || window.webkitAudioContext)();
var audioBuffer, fuenteDeReproduccion;
var stop = true;
var tiempo = 0;

function solicitarAudio(url) {
  var request = new XMLHttpRequest();
    //Inicializa el request ( la solicitud )
    url, // el url para el archivo de sonido
    true // asíncrono: true
  // el objeto arraybuffer se utiliza para almacenar datos binarios (archivos de sonido)
  request.responseType = "arraybuffer";
  // si hay respuesta
  request.onload = function() {
    audioCtx.decodeAudioData(request.response, function(buffer) {
      audioBuffer = buffer;

  //envía la solicitud

function reproducirAudio() {
    //1. crea la fuente de reproducción
    fuenteDeReproduccion = audioCtx.createBufferSource();
    // 2. establece la fuente de reproducción
    fuenteDeReproduccion.buffer = audioBuffer;
    // 3. Establece el valor de algunas propiedades
    // la propiedad playbackRate establece o devuelve la velocidad de reproducción del audio.
    fuenteDeReproduccion.playbackRate.value = .8;
    // 4. Conecta la fuente de reproducción con su destino ( altavoces, auriculares . . . etc )
    // 5. Inicia la reproducción

function detenerAudio() {

function audio(){  
  if (stop) {// si el audio está parado
    tiempo = audioCtx.currentTime;
    stop = false;
    boton.innerHTML = "||";//detener
  }else{// de lo contrario
    stop = true;
    boton.innerHTML = "&#9655;";//reproducir


// Utiliza el evento click para iniciar o detener la reproducción
boton.addEventListener("click", audio, false);

window.setInterval( function(){  
 if(audioBuffer && audioCtx.currentTime - tiempo >= audioBuffer.duration/.8){
    stop = true;
    boton.innerHTML = "&#9655;"//reproducir