i just added
select = $('#' + id);
length = $('#' + id + ' > option').length;
if (length > 20)
length = 20;
select.attr('size', length);
select.css('position', 'absolute');
select.focus();
and add into the select
onchange="$(this).removeAttr('size');"
onblur="$(this).removeAttr('size');"
to make the same appearance like the classic one (overlap the rest of html)