[html] 如何强制浏览器全屏？

function fullScreen() {
    var el = document.documentElement;
    var rfs = el.requestFullScreen || el.webkitRequestFullScreen || el.mozRequestFullScreen || el.msRequestFullscreen;
    if (typeof rfs != "undefined" && rfs) {
       rfs.call(el);
    }
    return;
}