固定位置CSS

TOP:
[css]
.toolbar{
position:fixed;
z-index:50;
top:0px;
left:0;
width:100%;
_top:expression(offsetParent.scrollTop);
_position:absolute;
}
[/css]
BOTTOM:
[css]
#bottombar {
position:fixed;
bottom:0;
z-index:50;
_position: absolute;
_bottom: auto;
_clear: both;
_top:expression(eval(document.compatMode && document.compatMode=='CSS1Compat') ? documentElement.scrollTop+(documentElement.clientHeight-this.clientHeight) - 6: document.body.scrollTop+(document.body.clientHeight-this.clientHeight) - 6);
[/css]