How to restrict the user that is already connected
<p>I am working in Asp.net and I want to restrict the user while login, if the same user is already logged in or already connected.. I am creating a table in sql server USERS_CONNECTED and placed a single field USER_ID in it. When ever a user is logged in it's id is searched in USERS_CONNECTED table. If id is not found then the user is allowed to connect and the user id is added in the said table. But the problem is when the X button(present on right top corner of the browser) is clicked to exit then the user id should be deleted from the USERS_CONNECTED table. WHERE SHOULD I WRITE THIS CODE ?? I MEAN ON WHAT EVENT ..
can anyone help...
Dev..</p>
