Detecting end of session with JS

Hello,

i'm using CF11,

part of my application.cfm file :

<cfapplication name="myapp" clientmanagement="yes" sessionmanagement="yes" sessiontimeout="#createtimespan(0,0,30,0)#">

When the user is logged in, session variable session.validlog is set to 1

The JS script (loaded with index.cfm) :

<script type="text/javascript">

  function session_checking()

  {

     $.post("ajax-session.cfm", function(data) {

         if(data === "-1")

         {

             window.location = "http:/myserver/login.cfm";

         }

         else

          {

          console.log('Session active') ;

         }

     });

  }

  var validateSession = setInterval(session_checking, 5000);

  </script>

the ajax-session.cfm file :

<cfswitch expression="#session.validlog#" >

  <cfcase value="1">1</cfcase>

  <cfdefaultcase>0</cfdefaultcase>

</cfswitch>

So : every 5 sec ajax-session.cfm is executed, if it return -1, user is redirected to the login page.

Issue :

When application session timeout is coming to 0, the user is not redirected to the login page ...

Any idea ?

Thanks,

Marc