How Responsive Web Design Works
The concept behind RWD, is relatively easy to explain, however implementation is a bit technical. However, it combines various languages in order to make it perfect. These languages includes HTML, CSS and Javascript. How it does it is by using CSS to hide objects not visible on the screen or due to the screen size, then shows it when that particular screen size is in used. Compared to the old form of web designing, whereby you have to design the Full Website and then design the Mobile website. It seemed a little bit tedious.
The Javascript on the other hands enables and detect view-able screen sizes and send some controls to the HTML and CSS codes. One of the Frameworks that enabled RWD to reach its potential is Bootstrap, which combines all the essential elements and focuses on the ones that are need for viewing at a particular time. take for example a user holding a mobile device would only be able to see view designed for the mobile View other wise the user cannot see anything more than that.
A typical use of a website to show if its responsive or not, is by re-sizing a browser, when it takes different shapes and sizes, it mimics that of a phone or tablet and the responsive code kicks in and shows the user exactly what needs to be display. If you need more tutorials on how to use RWD, Please download Bootstrap (google bootstrap) its an easy way for you to learn RWD and how it works.