Using HTML, CSS and JavaScript Create the following:

1. Create a login page and Accounts Page: (this part has been done)

2. When the user logs in, take them to the accounts page, and also add an accounts link to the navigation that they can go to.

3. This accounts link should only be visible if the user is logged in.

How do I make the accounts link become visible once the user logs in successfully? This is to be done using external CSS and external JavaScript files.