Fullscreen API

HTML

<button id="view-fullscreen">Fullscreen</button>

CSS

body {
    padding: 20px;
}

button {
    display: block;
    margin-bottom: 20px;
}

JavaScript

var viewFullScreen = document.getElementById("view-fullscreen");
if (viewFullScreen) {
    viewFullScreen.addEventListener("click", function () {
        var docElm = document.documentElement;
        if (docElm.mozRequestFullScreen) {
            docElm.mozRequestFullScreen();
        }
        else if (docElm.webkitRequestFullScreen) {
            docElm.webkitRequestFullScreen();
        }
    }, false);
}