JellySport/ProjectSourceCode/src/resources/js/navigation-bar/user/login.js

$(document).ready(function() {

  // When #user is clicked
  $('#user-profile-button').click(function() {

    $('#register-screen-container').hide();
    // Toggle the visibility of the login container
    $('#login-page').toggle();
  });

  $('#register-page-login-button').click(function() {
    event.preventDefault(); // Prevent the default action of following the link

    $('#register-screen-container').hide();
    $('#login-screen-container').show();
  });

});