页面可见度API

// 处理兼容性问题
let eventName, propName;
if(typeof document.hidden !== 'undefined') {
    eventName = 'visibilitychange';
    propName = 'hidden'
} else if(typeof document.msHidden !== 'undefined') {
    eventName = 'msvisibilitychange';
    propName = 'msHidden'
} else if(typeof document.webitHidden !== 'undefined') {
    eventName = 'webitvisibilitychange';
    propName = 'webitHidden'
}

document.addEventListener(eventName, () => {
    if(document[propName]) {
        // 隐藏
    } else {
        // 可见
    }
})