title.js

      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=');
      }
      });