js动态标题代码

    <script>var OriginTitile=document.title;
    var st;
    document.addEventListener('visibilitychange',function(){
    if(document.hidden){
    document.title="(つェ⊂)我藏好了哦";
    clearTimeout(st);
    console.log('hide');
    }else{
    document.title='(*´∇｀*) 被你发现啦~ '+OriginTitile;
    console.log('show');
    st=setTimeout(function(){
    document.title=OriginTitile;
    },4000);
    console.log('endChange=');
    }
    });</script>