3735 2006-09-16 04:44:43 +0000 Parse Error 2006-09-18 11:48:34 +0000 1 1 1 Unclassified CSSValidator CSS 2.0 CSS Validator PC Windows XP RESOLVED INVALID P2 normal --- 1 adulovic dave.null www-validator-cvs oldest_to_newest 11809 0 adulovic 2006-09-16 04:44:43 +0000 top: expression(document.body.scrollTop + document.body.clientHeight - offsetHeight); The above is a CSS expression I use often for keeping the footer stuck to the botom of the page. For some reason the validator returns the following error: Invalid number : top Parse Error I really would appreciate some clarification as to the status of CSS expressions. 11820 1 robin 2006-09-18 11:48:34 +0000 The 'expression' syntax is a Microsoft invention and not part of CSS. Seeing as this is an IE-only statement you could move it to a seperate stylesheet using conditional comments ( http://msdn.microsoft.com/library/default.asp?url=/workshop/author/dhtml/overview/ccomment_ovw.asp ). The stylesheet with the expression statement in will still be invalid, but it won't be picked up by the validator or other browsers. --> INVALID