code: function(){
      var _self = this,
        seriesCfg = _self.get('seriesOptions'),
        rst = 'line'; //默认类型是线
      Util.each(seriesCfg,function(v,k){
        rst = k.replace('Cfg','');
        return false;
      });
      return rst;
    }
docs: 获取默认的类型