浏览器全屏状态下监听esc

// 自定义一个函数-在退出全屏时进行的操作
function exitHandler() {
        if (!document.webkitIsFullScreen && !document.mozFullScreen && !document.msFullscreenElement) {
            console.log('退出了全屏')
        }
 }
// 监听fullscreenchange事件（全屏模式的变化）
if (document.addEventListener) {
        document.addEventListener('webkitfullscreenchange', exitHandler, false);
        document.addEventListener('mozfullscreenchange', exitHandler, false);
        document.addEventListener('fullscreenchange', exitHandler, false);
        document.addEventListener('MSFullscreenChange', exitHandler, false);
 }