Server Session timeout in Glassfish with custom page reload doesn't work

Question

I have Java EE app + Glassfish 4.1 + JSF Primefaces + Websockets. Session timeout configured for 30 minutes. It works on some pages.

<!-- Session Timeout in min -->
<session-config>
    <session-timeout>1</session-timeout>
</session-config>

However we have pages where we have custom js logic to reload page (invoked every 30 sec) to get latest result on page (kind of workaround if web-sockets won't work) which then invoke servlet on backend.

Is there any possibility to track is user inactive or check is this activity from user or it was auto-reload?