code: function(){
          if(!this._element){
              var elem;
              try{
                  elem = this._element = new Audio();
                  elem.addEventListener('canplaythrough', this._onAudioEvent, false);
                  elem.addEventListener('ended', this._onAudioEvent, false);
                  elem.addEventListener('error', this._onAudioEvent, false);
                  elem.src = this.src;
                  elem.volume = this.volume;
                  elem.load();
              }
              catch(err){
                  //ie9 某些版本有Audio对象，但是执行play,pause会报错！
                  elem = this._element = {};
                  elem.play = elem.pause = function(){
  
                  };
              }
          }
          return this;
      }
docs: HTMLAudioElement对象 
  @language=en
  Load audio file.