While working in osCommerce store, there are many places where you want to show some infromation only to logged in customers, and some thing else to non-logged in users. For this purpose, you need to check tep_session_is_registered(‘customer_id’) variable and show different blocks of content.
In the following code, I have put togther an example where user is shown login link if he’s not logged in, and My Account, Checkout, Shopping Cart and Logoff links if he’s logged in.
$nav = ''; echo $nav ;
Hope that helps.