• Create a directory called “js”; it seems that the directory name should not start with an underscore (does jekyll treat directory names starting with an underscore in a special way? need to be confirmed).
  • Download the following three files (from https://ajax.googleapis.com/ajax/libs/jquery/1.5.2/jquery.min.js and https://github.com/jeromeetienne/jquery-qrcode) to this directory:
    • jquery.min.js
    • jquery.qrcode.js
    • qrcode.js
  • Include the following lines in _includes/head.html:
<script type="text/javascript" src="/js/jquery.min.js"></script>
<script type="text/javascript" src="/js/jquery.qrcode.js"></script>
<script type="text/javascript" src="/js/qrcode.js"></script>
  • Include the following lines in _includes/footer.html:
<div id="qrcode_footer"></div>
<script type="text/javascript">
    jQuery('#qrcode_footer').qrcode({
        render  : "table",
        text    : "http://fjdu.github.io/website/2015/09/05/qrcode.html"
    }); 
</script>

I also found a bug in jekyll: highlight within list will break the list numbering.