code: function(border) {
      var xml = this.map.border.toXml(border);
      var index = this.index.border[xml];
      if (index === undefined) {
        index = this.index.border[xml] = this.model.borders.length;
        this.model.borders.push(xml);
      }
      return index;
    }
docs: ========================================================================= Borders