Fullscreen websites are those that fill the entire browser window no matter what the screen resolution. As screen sizes and resolutions are growing and internet speed is increasing, it seems like more and more web designers use full screen images for their website backgrounds. Oversized background images can be stunning and have more visual impact than the traditional tiled background graphics.
The browser viewport is a fluid medium. There are many options to produce full screen backgrounds and ways to place HTML over the images. Some websites rely on a flexible layout to stretch across the browser window, while others use large, fixed size images to produce full backgrounds.
External Links: Using HTML5 Fullscreen API | Fullscreen Support