I have the same question as therockfordfiles posted in the PHP Application Design topic. They said it is a javascript thing, so I post same question here.

"How do I create a web page navigation system so that when I click on a link, only part of the page changes (not the url) and the rest remains the same?
For example, I have a web page. In that web page there's tabs. When clicking on a tab, I want the tab to change along with its respective content."