This script utilizes the JQuery UI Library in order to open a modal dialog with terms of use that the user must explicitly agree to before accessing the page. When the user accepts the terms, a session cookie is passed to her browser so that she will not have to accept the terms again each time the page reloads. Cookies are passed using Klaus Hartl's JQuery-Cookie script: https://github.com/carhartl/jquery-cookie/blob/master/jquery.cookie.js

A full, step-by-step discussion of how this script can be implemented in a Drupal site is provided at http://techneblog.com/article/using-jquery-ui-add-effects-drupal-site-part-i and http://techneblog.com/article/using-jquery-ui-add-effects-drupal-site-part-ii.