https://static-event.benghuai.com/new_mihoyo_homepage/js/topbar.js?v=228

1var bar_key = 0;
2top_bar(); 
3function GetQueryString(_name)
4{
5    var reg = new RegExp("(^|&)"+ _name +"=([^&]*)(&|$)");
6    var r = window.location.search.substr(1).match(reg);
7    if(r!=null)
8        return(unescape(r[2])); 
9    return null;
10}
11
12function top_bar(){
13    if($(document).scrollTop() > 48 && bar_key==0){
14        $("#top-bar").addClass("fixed");
15        bar_key = 1;
16    }else if($(document).scrollTop() < 48 && bar_key==1){
17        $("#top-bar").removeClass("fixed");
18        bar_key = 0;
19    }
20    $(document).scroll(function(){  
21       // console.log($(document).scrollTop());
22        if($(document).scrollTop() > 48 && bar_key==0){
23            $("#top-bar").addClass("fixed");
24            bar_key = 1;
25        }else if($(document).scrollTop() < 48 && bar_key==1){
26            $("#top-bar").removeClass("fixed");
27            bar_key = 0;
28        }
29    });
30}