text: exports.loadROM = function(nes, file, callback) {
      if (file.size === 0) {
          return
      }
      let reader = new FileReader();
      reader.onload = function () {
          nes.load(this.result);
          if (typeof callback==='function') {
              callback(nes);
          }
      };
      reader.readAsBinaryString(file);
  };
  