At its simplest it is a delivery method that adapts the HTML/CSS/JavaScript for the platform and browser that is being used to view. Simple browsers, as you might find on a basic mobile phone, may not understand JavaScript or media queries, so therefore best practice is to create a basic web site without JavaScript, and then create extra coding for an improved web experience on smart phones and computers with more sophisticated browsers and screen resolutions. This is an alternative to the previous technique use by web designers of producing a site for the best possible situation and allowing it degrade gracefully as browsers and platform reduce in capability.

With JavaScript, jQuery, and jQuery Mobile, a web designer can test for browser support for certain HTML/CSS features, a particular platform and/or browser.

A freelance web designer can creates responsive web designs by:

• Polyfilling, a technique where additional software allows a particular browser or a version of a browser to appear to have facilities that are lacking when compared to other browsers.
• Fluid proportion-based grids where page element sizing is set in relative units like percentages, rather than absolute units like pixels or points.
• Scalable images to that do not affect the layout of the web page design
• Media queries allow the page to use different CSS style rules based on characteristics of the device the site is being displayed on, most commonly the width of the browser is critical.
• Server-side and client side elements (PHP, JavaScript and jQuery) can be combined to dynamically create faster loading sites where download speed is slower such as mobile phone networks is detected albeit at a design cost.