Responsive Web Design
Responsive Web Design (RWD) is a technique for creating a website design which fits optimal on a wide range of screen sizes (from a desktop computer screen to small mobile device screen).
The term Responsive Website may also known as “Mobile-friendly Website”.
There are many differences between a website with an old layout (best fit on desktop computers) and a responsive website. The key/most-important features for a responsive website (comparing with the old-layout websites) are: having different navigation menus regarding the screen sizes, and preventing the scroll bar to be appeared when viewing the website on smaller screens; this can be gained by using different stylesheets for different screen sizes.