code: function set(name, element, previous, attrs) {
    if (set.handlers[name]) {
      set.handlers[name](name, element, previous, attrs);
    } else if (attrs[name] != null && previous[name] !== attrs[name]) {
      element.setAttribute(name, attrs[name]);
    }
  }
docs: Sets an attribute.
  
  @param  String name      The attribute name to set.
  @param  Object element   A DOM element.
  @param  Object previous  The previous state of attributes.
  @param  Object attrs     The attributes to match on.