js 动态修改浏览器标签的 title

<script>

    var cur_title = document.title;
    var titles = ["(｡•ˇ‸ˇ•｡)咦，你什么时候回来", "(((┏(;￣▽￣)┛嗨，我一直在", "∑(っ°Д°;)っ哎呦，藏起来了",
        "(｡ŏ_ŏ)哼，你居然走了", "(✪ω✪)哈哈，等你来撩"];
    var titles_back = ["你回来啦(^_−)☆", "欢迎回来(づ￣ 3￣)づ"];
    document.addEventListener('visibilitychange', function () {
        var isHidden = document.hidden;
        var title_random = titles[Math.floor((Math.random() * titles.length))];
        var title_random_back = titles_back[Math.floor((Math.random() * titles_back.length))];
        if (isHidden) {
            document.title = title_random;
            setTimeout(function () {
                document.title = cur_title;
            }, 3000);
        } else {
            document.title = title_random_back;
            setTimeout(function () {
                document.title = cur_title;
            }, 1500);
        }
    });


</script>