sometimes this error happens because the html element that you are trying to access using it's id does not load yet. You can check if when you try to access $('comments_list').down(0) the element exists in the HTML. You can check using the firebug.
sometimes this error happens because the html element that you are trying to access using it's id does not load yet. You can check if when you try to access $('comments_list').down(0) the element exists in the HTML. You can check using the firebug.