What the method called

[monkeytooth]

Whats the method called where you go to a page, and when you scroll up/down a particular element seems to be fixed and scrolls with you, however if it reaches a certain point scrolling up or down it stops at said point as to not over lap another piece of the template the designer has made that may stretch further out.

[cssfreakie]

#element{
position: fixed;
}