code: function manageAttr(node, direction, mode, id) {
      var attrName = 'data-baron-' + direction + '-id'
  
      if (mode == 'on') {
          node.setAttribute(attrName, id)
      } else if (mode == 'off') {
          node.removeAttribute(attrName)
      }
  
      return node.getAttribute(attrName)
  }
docs: set, remove or read baron-specific id-attribute @returns {String|null} - id node value, or null, if there is no attr