showdownjs/src/subParsers/hashBlock.js

showdown.subParser('hashBlock', function (text, options, globals) {
  'use strict';
  text = text.replace(/(^\n+|\n+$)/g, '');
  return '\n\n~K' + (globals.gHtmlBlocks.push(text) - 1) + 'K\n\n';
});