How do I position a div at the bottom center of the screen

Question

I have this css:

#manipulate
{
  position:absolute;
  width:300px;
  height:300px;
  background:#063;
  bottom:0px;
  right:25%;
}

I have t

Answer 1

You can center it using negative margins BUT please note that it'll center exactly on the center of the screen IF any containing div is NOT SET to position:relative;

For example. http://jsfiddle.net/aWNCm/

So, best way to exactly center this div is to set correct properties position properties for its containing divs too otherwise it will be lost in some random ways.