URLs + Session Tracking

[Hussein Baghdadi]

Hola ranchers.
I have a few questions.
1. If my context was (mycontext) and I have a servlet which it's url-pattern is shopping/addToCart
how to point to this servlet from a JSP page?
should I write:
<a href="shopping/addToCart">Add To My Cart</a>
<a href="/mycontext/shopping/addToCart">Add To My Cart</a>
<a href="http://localhost:8080/shopping/addToCart">Add To My Cart</a>
I have tried the first one, but it is destroying my app.
what is the approach that used in the real sites?
2. I faced this problem:
In my app, the session tracking is ok, I have added some books to my cart, then I click show my cart.
it is fine with IE6, but when testing it with opera7, it don't work with a consistent way (I am enabling cookies with opera).
the first time a clicked show my cart it work, then I added some new books and when clicked show my cart again, it doesn't show the new added books.
If the application work with IE6 , why it don't with Opera7?