In a new posting from Codewalkers.com today, Hermawan Haryanto has a tutorial that shows you how to create an auto-refreshing page that only does so when something has changed.

From Smart Auto Refresh: Have you ever thought about how to make a website able to reload itself whenever the content inside the page is updated through another application or another page? Well I have. In this article, I will show you how to build a Smart Auto Refreshing report page.

His example, a "shoutbox" application, is a way for a site's users to both interact with the site admins and others viewing the site (like a mini-forum). He gives all the code and DB structure you'll need to get the example working. The key to the script is the use of javascript to set cookies and loop based on times to refresh the page. The script is pretty simple, so integrating it into your site should be a pretty simple task. Plus, building on the foundations of this idea, web applications can become "more aware" when they data inside them changes.