[jQuery] Each function gives errors in IE6

[Shane Riley]

I've got a simple each function that finds every subnav and assigns it
a vertical position equal to half of the subnav's height. This works
great in all modern browsers, but in IE6 I get errors from each of the
two lines within the function. Here's the problem function:

$(".subnav").each(function(i)
        {
                top = (parseInt($(this).height()) / 2) - 6;
                $(this).css("top", ("-" + top + "px"));
        });

When I view the page in IE6, I get an error saying "Not implemented".
If I comment out the line setting the top variable, I get an error
saying "Invalid argument". Initially I was thinking the problem was in
setting the CSS property for top, but now it seems something else is
up.