clip
This property sets the coordinates of the clipping rectangle that houses the content of elements. The allowed clipping shape is a rectangle defined rect (top right bottom left) where the values specify offsets from the respective sides of the containing box. Eventually, other shapes may be possible.
Example
#div1 {position: absolute; left: 20px; top: 20px;
width:100px; height:100; clip: rect(10px 90px 90px 10px);}
Browser and CSS Support Notes
CSS2
IE 4, 5 (buggy), 5.5, 6
Nav 6, 7
Opera 5, 6, 7