I'm working on a web site for a (German) Teamspeak server I made and I just noticed that when I click a link on my site it just shows a white page until the content is fully loaded and ready to show.

Now my question is how does YouTube (and some other sites) work in that part? YouTube keeps showing the whole site after you clicked on something for example. There is just a small loading bar at the top but only main part of the site loads while the side-menu and the header just stay exactly as they were before.

Hope you understand what I mean (if not feel free to ask so I can try to explain it a bit better).

Web site im working on (German): http://dissconnection.de/ If you click on something in the header you will see that it gets blank for a short moment and what I want is that the header stays where it is while loading.

(I think that's possible with frames but I don't want to use them too often and I think YouTube doesn't uses frames for that either).