Static applications and websites render in the user’s browser without the need for server side processing, this means that all the rendering of HTML, CSS, and JavaScript is done on the client side, rather then relying on server side technologies. Whilst traditionally managing static websites and applications may seem like hard work, the medium has come on leaps and bounds over the past few years to the extent that it’s now perfectly feasible to run heavy content, rich media websites, and applications entirely in the browser – Good times!
So grabbing and rendering UI elements doesn’t need roundtrips to your server, instead relying on the browser, which actually saves a heck of time for the user.
Also: http://www.staticgen.com/