javascript STYLE bottom

For an absolute-positioned element, defines the position of the bottom edge of an element's box (content plus bottom padding, border, and/or margin) relative to the bottom edge of the next outermost block content container. IE for Windows and Netscape 6 do something unexpected when the positioned element uses the root positioning context. Instead of using the bottom of the document as the comparative edge, these browsers use the bottom of the browser window space (the viewport in CSS terminology). This means that the precise bottom position of the element varies with the user's browser window size. IE 5 for the Macintosh uses the document's bottom as the comparative edge. This discrepancy makes it more practical to use the bottom property for a positioned element nested inside another positioned element. When the element is relative-positioned, the offset is based on the bottom edge of the inline location where the element would normally appear in the content.