code: function _addEvent(object, type, callback) {
          if (object.addEventListener) {
              object.addEventListener(type, callback, false);
              return;
          }
  
          object.attachEvent('on' + type, callback);
      }
docs: cross browser add event method
  
  @param {Element|HTMLDocument} object
  @param {string} type
  @param {Function} callback
  @returns void