参照: http://webfx.eae.net/dhtml/cssexpr/cssexpr.html
#fixedElement {
position: fixed;
top: 100px;
left: 80px;
/* IE5 later && javascript-on */
position: expression('absolute');
top: expression(documentElement.scrollTop + 100 + 'px');
left: expression(documentElement.scrollLeft + 80 + 'px');
}