code: function pro(){
              var src = this.src;
             
              //Remove events cause audio trigger this event more than once(depends on browser)
              if (this.removeEventListener) {  
                  this.removeEventListener('canplaythrough', pro, false);     
              }
             
              ++j;
              //if progress callback, give information of assets loaded, total and percent
              if (onprogress) 
                  onprogress({
                      loaded: j, 
                      total: total, 
                      percent: (j / total * 100),
                      src:src
                  });
  				
              if(j === total && oncomplete) oncomplete();
          }
docs: Progress function