From http://www.w3schools.com (Copyright Refsnes Data)

ASP IsClientConnected Property

Response Object Reference Complete Response Object Reference

The IsClientConnected property indicates if the client has disconnected from the server.

Syntax

response.IsClientConnected

Examples

<%
If response.IsClientConnected=true then
  response.write("The user is still connected!")
else
  response.write("The user is not connected!")
end if
%>

Response Object Reference Complete Response Object Reference

From http://www.w3schools.com (Copyright Refsnes Data)