Update a ToC in Markdown

markdown-toc.js

// To update the TOC, replace 'h3' with the level
// of your headings,
// open a debugging console on the file.md page on GitHub
// and execute:
$('article>h3').map(function(i){
  var txt = $(this).text();
  var href= $(this).find('a').attr('href');
  return "- [" + txt + "](" + href + ")";
}).get().join('\n');