fullscreenchange事件
fullscreenchange：當窗口大小改變時觸發
isFullscreen：全局變量
window.addEventListener("fullscreenchange", function (e) {
if (isFullscreen) {
$('.fullScreen').attr('data-original-title', "退出全屏");
} else {
$('.fullScreen').attr('data-original-title', "全屏顯示");
}
})