点击按钮，进入全屏与退出全屏切换

<script>
    // 进入全屏：
    function entryFullScreen() {
        var docE = document.documentElement;
        if (docE.requestFullScreen) {
            docE.requestFullScreen();
        } else if (docE.mozRequestFullScreen) {
            docE.mozRequestFullScreen();
        } else if (docE.webkitRequestFullScreen) {
            docE.webkitRequestFullScreen();
        }
    }

    // 退出全屏
    function exitFullScreen() {
        var docE = document;
        if (docE.exitFullscreen) {
            docE.exitFullscreen();
        } else if (docE.mozCancelFullScreen) {
            docE.mozCancelFullScreen();
        } else if (docE.webkitCancelFullScreen) {
            docE.webkitCancelFullScreen();
        }
        // 全屏开启
    form.on('switch(fullscreen)',function(data){
        var  fValue=data.elem.checked;
        localStorage.setItem('funnscreen_info',fValue);
    });
    $(document).ready(function(){
        var fScreen=localStorage.getItem('fullscreen_info');
        if(fScreen&&fScreen!='false'){
            var fScreenIndex=layer.alert('按ESC退出全屏',{
                title:'进入全屏提示信息',
                skin:'layui-layer-lan',
                closeBtn:0,
                anim:4,
                offset:'100px'
            },function(){
                entryFullScreen();
                    $('#FullScreen').html('<i class="larry-icon larry-quanping"></i>退出全屏');
                    layer.close(fScreenIndex);
                }
            )
        }
    })
        // 全屏切换
        $('#FullScreen').bind('click', function() {
            var fullscreenElement =
                document.fullscreenElement ||
                document.mozFullScreenElement ||
                document.webkitFullscreenElement;
            if (fullscreenElement == null) {
                entryFullScreen();
                $(this).html('<i class="larry-icon">&#xe604;</i>退出全屏');
            } else {
                exitFullScreen();
                $(this).html('<i class="larry-icon">&#xe604;</i>全屏');
            }
        })
</script>