The Global.asa file is an optional file that can contain declarations of objects, variables, and methods that can be accessed by every page in an
ASP application. All valid browser scripts (JavaScript, VBScript, JScript, PerlScript, etc.) can be used within Global.asa.
The Global.asa file can contain only the following:
Application events
Session events
<object> declarations
TypeLibrary declarations
the #include directive
Note: The Global.asa file must be stored in the root directory of the ASP application, and each application can only have one Global.asa file.
Events in Global.asa
In Global.asa you can tell the application and session objects what to do when the application/session starts and what to do when the
application/session ends. The code for this is placed in event handlers. The Global.asa file can contain four types of events:
Application_OnStart – This event occurs when the FIRST user calls the first page from an ASP application. This event occurs after the Web
server is restarted or after the Global.asa file is edited. The “Session_OnStart” event occurs immediately after this event.
Session_OnStart – This event occurs EVERY time a NEW user requests his or her first page in the ASP application.
Session_OnEnd – This event occurs EVERY time a user ends a session. A user ends a session after a page has not been requested by the
user for a specified time (by default this is 20 minutes).
Application_OnEnd – This event occurs after the LAST user has ended the session. Typically, this event occurs when a Web server stops. This
procedure is used to clean up settings after the Application stops, like delete records or write information to text files.
A Global.asa file could look something like this:
<script language=”vbscript” runat=”server”>sub Application_OnStart
””some code
end subsub Application_OnEnd
””some code
end subsub Session_OnStart
””some code
end subsub Session_OnEnd
””some code
end sub</script>
Note: We cannot use the ASP script delimiters (<% and %>) to insert scripts in the Global.asa file, we will have to put the subroutines inside the
HTML <script> tag.
More info at https://www.w3schools.com/asp/asp_globalasa.asp