浏览器全屏非全屏切换

    //进入全屏
    function requestFullScreen() {
        var de = document.documentElement;
        if (de.requestFullscreen) {
            de.requestFullscreen();
        } else if (de.mozRequestFullScreen) {
            de.mozRequestFullScreen();
        } else if (de.webkitRequestFullScreen) {
            de.webkitRequestFullScreen();
        }
    }

    //退出全屏
    function exitFullscreen() {
        var de = document;
        if (de.exitFullscreen) {
            de.exitFullscreen();
        } else if (de.mozCancelFullScreen) {
            de.mozCancelFullScreen();
        } else if (de.webkitCancelFullScreen) {
            de.webkitCancelFullScreen();
        }
    }