At the moment there is no way to view an MGRS or Latitude Longitude grid on the map canvas for the JavaScript API. It would be ideal if as a user I could click a toggle button that displays an MGRS grid on top of the world map. The same goes for a Lat Lon grid.
This ability is possible on the Flex API as I have seen in the examples, but not in JavaScript API.A snapshot from the Flex API is shown above. Please replicate this in the JavaScript API.