code: function loadCSS(url, callback, fail) {
          var node = DOC.createElement('link');
          node.rel = 'stylesheet';
          node.type = "text/css";
  
          cssCallback(node, callback, fail);
  
          node.href = url;
          HEAD.insertBefore(node, BASEELEMENT);
          return $;
      }
docs: 加载css文件
  @param  {[type]}   url      [description]
  @param  {Function} callback [description]
  @return {[type]}            [description]