I'm working on building a forum in PHP and am trying to include a feature that would log a user out after a certain amount of time. It would also direct them back to the login page after the elapsed time. I've built the forum using separate php pages for the connection, login, logout, index, header, footer and other pages. I include the connection and header php files at the top of every page. Where would I place a script to have it communicate throughout the forum and effectively timeout a user?