How does an ASP website obtain the number of online users?

My global. asa file is as follows:
<Script language = "VBScript" RUNAT = "Server">
'Session _ OnStart: run when the customer runs any page of ASP Application for the first time
'Session _ OnEnd when a client's Session times out or exits the application
'Application _ OnStart is run when any customer accesses the homepage of the Application for the first time.
'Application _ OnEnd: run when the website's WEB server is closed
Sub Application_OnStart
VisitorCountFilename = Server. MapPath ("../VisitCount.txt ")
Set FileObject = Server. CreateObject ("Scripting. FileSystemObject ")
Set Out = FileObject. OpenTextFile (VisitorCountFilename, 1, FALSE, FALSE)
Application ("visitors") = Out. ReadLine
Application ("NowPeopleNumber") = 0
Application ("VisitorCountFilename") = VisitorCountFilename
End Sub
'================================================ ============================
SUB Application_OnEnd
Set FileOutObject = Server. CreateObject ("Scripting. FileSystemObject ")
Set Out = FileOutObject. CreateTextFile (Application ("VisitorCountFilename"), TRUE, FALSE)
Out. WriteLine (application ("visitors "))
End Sub
'================================================ ============================
Sub Session_OnStart
Session. Timeout = 30
Application ("visitors") = Application ("visitors") + 1
Application ("NowPeopleNumber") = Application ("NowPeopleNumber") + 1
Session ("ID") = Session. SessionID
Session ("UserName") = 0' does not exist
End Sub
'================================================ ============================
Sub Session_OnEnd
Application ("NowPeopleNumber") = Application ("NowPeopleNumber")-1
End Sub
</SCRIPT>
The total number of visitors in this example will be stored in the visitcount.txt file. I think the Application ("NowPeopleNumber") should have saved
The number of online users can be displayed on the home page, but I found that when I close my browser and open the home page
The number of online users increased by 1. That is to say, Session_OnEnd is not executed. Why? There are other ways to get
Online users? Thank you for posting this article for the first time.