JSFiddle - React, Tailwind, and code Playground

JavaScript

var player = new Audio();
player.setAttribute('src', 'http://dl.dropbox.com/u/95730813/1.mp3');
player.load();

var time = 276.331;

var onProgress = function(){
   var buffered;
   try{
       buffered = (Math.floor(this.buffered.end(0) * 1000) / 1000) || 0;
   }catch(e){}
   if(time && Math.abs(time - buffered) < 0.1){
       console.log('Buffered: 100%');
       this.removeEventListener('progress', onProgress);
   }else{
       var percent = Math.ceil(buffered / time * 100);
       
       percent = Math.min(100, Math.max(0, percent));
       if(!isNaN(percent)){
           console.log('Buffered: '+ percent +'%');
       }
    }
}

player.addEventListener('progress', onProgress);

$(document).ready(function(){
    player.play();
});