showdownjs/src/subParsers/makehtml/blockQuotes.js

showdown.subParser('makehtml.blockQuotes', function (text, options, globals) {
  'use strict';

  text = globals.converter._dispatch('makehtml.blockQuotes.before', text, options, globals);

  text = text.replace(/((^ {0,3}>[ \t]?.+\n(.+\n)*\n*)+)/gm, function (wholeMatch, m1) {
    var bq = m1;

    // attacklab: hack around Konqueror 3.5.4 bug:
    // "----------bug".replace(/^-/g,"") == "bug"
    bq = bq.replace(/^[ \t]*>[ \t]?/gm, '¨0'); // trim one level of quoting

    // attacklab: clean up hack
    bq = bq.replace(/¨0/g, '');

    bq = bq.replace(/^[ \t]+$/gm, ''); // trim whitespace-only lines
    bq = showdown.subParser('makehtml.githubCodeBlocks')(bq, options, globals);
    bq = showdown.subParser('makehtml.blockGamut')(bq, options, globals); // recurse

    bq = bq.replace(/(^|\n)/g, '$1  ');
    // These leading spaces screw with <pre> content, so we need to fix that:
    bq = bq.replace(/(\s*<pre>[^\r]+?<\/pre>)/gm, function (wholeMatch, m1) {
      var pre = m1;
      // attacklab: hack around Konqueror 3.5.4 bug:
      pre = pre.replace(/^  /mg, '¨0');
      pre = pre.replace(/¨0/g, '');
      return pre;
    });

    return showdown.subParser('makehtml.hashBlock')('<blockquote>\n' + bq + '\n</blockquote>', options, globals);
  });

  text = globals.converter._dispatch('makehtml.blockQuotes.after', text, options, globals);
  return text;
});