The user will be inside the store and able to browse immediately. They'll be anonymous until they add an item to their shopping cart, at which time they'll be assigned a session identifier.
If a user has cookies enabled in their browser, they will get their original shopping cart back, even if they don't come back for a few months. But a user whose browser doesn't support cookies will get a new shopping cart each time they enter the store.
To allow someone to retrieve their shopping cart, submit a form with an Action of Login, and either their Username or their EMail and their password.
<form method="POST" action="welcome.html"> <input type="hidden" name="Action" value="Login"> E-mail Address: <input type="text" name="EMail" value="" size="20" maxlength="40"> Password: <input type="password" name="Password" value="" size="20" maxlength="20"> <input type="submit" value="Login"> </form>
If someone wishes to log out and delete the cookie from their browser, you just need to create a form which submits a hidden element named Logout set to yes. If you want the store to be a one-shot simple purchase system, you can submit this element on the purchase screen to achieve an instant logout if the purchase succeeds.
<form method="POST" action="leaving.html"> <input type="hidden" name="Logout" value="yes"> <input type="submit" value="Logout"> </form>