Gone are the days when one could write a site for a single family of devices — mostly desktop browsers. Today, desktop browsers are just one type of device to be concerned about. A multi-device website is critical for any type and size of business. Even more critical for any business is avoiding poor-quality websites that don't distinguish the underlying devices, whether they be smart phones, tablets, mini-tablets, smart TVs, wearable devices, or whatever else the industry may produce. This course explores the pros and cons of Responsive Web Design - using CSS media queries - and a much more sophisticated and powerful server-side approach based on WURFL, the same technology used by Facebook and Google. Through WURFL, you can gain knowledge about the effective capabilities of the device, and can implement appropriate use-cases for different classes of mobile and legacy devices.