code: function(attr, val) {
        return val === undefined ? (this.length ? this[0].getAttribute(attr) : null) : this.each(function(index, el) {
          el.setAttribute(attr, val);
        });
      }
docs: attr method
  get or set an attribute
  @param  {string}          attr  - attribute name
  @param  {string}          [val] - attribute value
  @return {(string|object)}         attribute value or this