Did you know web browsers are starting to support a programmatic fullscreen mode? This blog post goes into an in-depth explanation, but if you just want to see it in action, click the photo below. Click the photo again to get out of it (or press "esc" on your keyboard).
Your browser supports fullscreen mode using the following methods and properties: element.webkitRequestFullScreen(), document.webkitCancelFullScreen(), and document.webkitIsFullScreen.
Photo credit: instagr.am/p/SHLkw