<input id="Button1" type="button" value="开始全屏" onclick="kaishi()" />

<input id="Button2" type="button" value="关闭全屏" onclick="guanbi()" />

<script>

    function kaishi()

    {

        var docElm = document.documentElement;

        //W3C

        if (docElm.requestFullscreen) {

            docElm.requestFullscreen();

        }

            //FireFox

        else if (docElm.mozRequestFullScreen) {

            docElm.mozRequestFullScreen();

        }

            //Chrome等

        else if (docElm.webkitRequestFullScreen) {

            docElm.webkitRequestFullScreen();

        }

            //IE11

        else if (elem.msRequestFullscreen) {

            elem.msRequestFullscreen();

        }

    }

    function guanbi() {

        if (document.exitFullscreen) {

            document.exitFullscreen();

        }

        else if (document.mozCancelFullScreen) {

            document.mozCancelFullScreen();

        }

        else if (document.webkitCancelFullScreen) {

            document.webkitCancelFullScreen();

        }

        else if (document.msExitFullscreen) {

            document.msExitFullscreen();

        }

    }

    document.addEventListener("fullscreenchange", function () {

        fullscreenState.innerHTML = (document.fullscreen) ? "" : "not ";

    }, false);

    document.addEventListener("mozfullscreenchange", function () {

        fullscreenState.innerHTML = (document.mozFullScreen) ? "" : "not ";

    }, false);

    document.addEventListener("webkitfullscreenchange", function () {

        fullscreenState.innerHTML = (document.webkitIsFullScreen) ? "" : "not ";

    }, false);

    document.addEventListener("msfullscreenchange", function () {

        fullscreenState.innerHTML = (document.msFullscreenElement) ? "" : "not ";

    }, false);

</script>