Node (server) and Dojo (client): where to store the username client-side?

I am writing a simple application. I wrote the login/password screens, which simply set a session variable:

if( docs.password == req.body.password ) {
   errors.push({ field:'password', message: 'Password Match!', mustChange: false } );
   res.json( { response: 'OK' } , 200);
   req.session.loggedIn = true;
   req.session.login = req.body.login;

Once Login goes through, the client is redirected to the actual application (as per normal). However, at that point the client no longer knows what login name they used to login! (I am talking about the Javascript that runs in the browser)

As you can see, I am saving the user name in the session. However, when the client loads the "application" HTML page, they don't have their own login name as it's a brand new page with brand new Javascript (which is unaware of what username they used to login a moment earlier).

I could embed it somewhere in the page's HTML (somewhere like a global JS variable in the page's body?) since it's in the session, but...

How is this "normally" done? What's a good pattern to go about this?

Merc.