This page is a work in progress.You can help improve it. →

Introduction to Responsive Web

Now that we can create a semantic web page, style it with CSS, and control its layout with CSS layout technologies this lesson will cover how to cope with the reality that visitors to our page/application will use many different devices that are different sizes, pixel densities, and perhaps even with different capabilities.

Being able to respond to these differences while maintaining a single code base gives us the best chance of providing all our users the best experience.

Learning Objectives

  • Creating a mobile-first design
  • Creating a responsive design
  • Using media queries to build responsive; mobile first UIs.


For Web developers, it is now fairly common to be called upon to create a Web site or app that changes its user interface depending on the browser or device accessing the site to provide an optimized experience. One approach to this is to create different versions of your site/app for different platforms or browsers and serve them appropriately after detecting which browser or platform is looking at your site. But this is increasingly inefficient: browser sniffing is inherently error prone, and maintaining multiple copies of your code can turn out to be a nightmare.

It is usually much better to create a single version of your code which doesn't care about what browser or platform is accessing the site. This tends to be termed responsive design or adaptive design, two related but different approaches.

There are disadvantages to this approach as well. If the content, layout, and functionality need to change greatly for different devices, it may not be such a good approach. Also, taking an existing site and adding responsiveness to it, to make it mobile/tablet friendly, can be a lot more effort than just creating a separate mobile site or app, especially if it is a sprawling enterprise site.

© 2017 - 2021; Built with ♥ in St. Petersburg, Florida.