Parallax is defined as “a difference in the apparent position of an object viewed along two different lines of sight.”
The Parallax effect or, parallax scrolling, in web design is a technique using layered images that move around at the website in different speeds/perspectives in the website, creating a sort of 3D illusion.
In early video games, images were constructed of independent layers scrolling at different speeds to give the effect of motion, giving some layers the impression of being farther away than others – and thus the illusion of depth. This was called parallax scrolling, but it only worked when the mouse or cursor was moved. Commercial companies are using parallax scrolling techniques to attract customers to their websites .One way to use this technique is a historical timeline, telling visitors to the site about the history of the company.
Techniques are being developed that will minimize, or eliminate the need to continually “point and click” to get information or to access the website. The program will logically lead users to where they want or need to go. Essentially, the website works like a movie, with sequences of images and action, graphics and motion, to guide the user to a site, a decision or a conclusion.
Mobile sites have different requirements than sites viewed on a desktop, but many mobile sites haven’t been designed for parallax-scrolling. But that is changing, partly at least to parallax responsive web designs and the increasing use of mobile devices to do more than phone home, requires websites to be available without distortion and excessive “point and click” actions.
But it has its limitations. It’s still not widely used now because of slow load times. It’s an idea that‘s ahead of the time, and it’s waiting for the technology to catch up.