$15
Update the system status: change the <title to reflect the current page
Update the system status: give a class of "active" to the <li navigation elements
Fix the endpoints, so that navigating to them directly does not cause a 404 error.
Implement History.js: https://github.com/browserstate/history.js/
make a fallback for browsers that are not Java-Script enabled
You can try this in Chrome. If you'd like to turn JavaScript off or on for all sites:
Click the Chrome menu in the top right hand corner of your browser
Select Settings
Click Show advanced settings
Under the "Privacy" section, click the Content settings button.
In the "Javascript" section, select "Do not allow any site to run JavaScript" or "Allow all sites to run JavaScript (recommended)"