i realized the other day that the markdown-extra plugin i am using for text markup was generating non-unique footnote anchors, resulting in any footnote #1 in a blog entry on referring back to footnote #1’s anchor in the very first blog on a page with multiple blog entries. not good. so, i had a look at the markdown-extra.php’s source — it already contains a variable fn_id_prefix but that is initialized to the empty string

# Prefix for footnote ids. var $fn_id_prefix = “”;

yet, that is a nice starting point, because all we have to do to get unique anchors is to add the following line of code in _hashHTMLBlocks_inMarkdown():¹

$this->fn_id_prefix = md5($text);