You can go one step further and Take a RESS approach (REsponsive design & Server Side detection). Using a device detection repository such as 51Degrees.mobi for true device detection. Easily allowing you to detect the individual hardware devices of your users as well as their browsers and operating systems. Updated weekly so you'll never need to worry about new devices not being detected correctly. It will also improve performance as the processing doesn't need to be performed by the client.