The term parallax, when used in the context of computer graphics, especially in video games, refers to the technique of using multiple background layers that scroll at slightly different speeds to create the illusion of depth. Although not as widely deployed in modern gaming, thanks to the advent of richer 3D graphics engines, parallax is still seen frequently in portable gaming devices, and increasingly, on the Web.
A parallax effect is achievable using pure CSS, as demonstrated nicely by the Silverback site (see http://silverbackapp.com/ for the effect, and http://thinkvitamin.com/design/how-to-recreate-silverbacks-parallax-effect/ for the details on how it was implemented). This application of parallax will only become apparent when the window is resized, which is a fantastic effect when the window is resized, but doesn't help us if we want the effect to take more of a center stage.
