position: function(pos) does not work under IE6

the following does not work in IE6

minTop = top = doc.scrollTop()

as i.e. interprets top to be window.top which is readonly.

Therefore I've changed it to read

top = doc.scrollTop(), minTop = top

full line below

var wnd = $(window), doc = $(document), top = doc.scrollTop(), minTop = top , left = doc.scrollLeft();