Part of services.js

else if (match[4]) { // URL & e-mail
  if (!options.noLinks) {
    var matchEmojiInURL;
    if (match[4].match(emojiRegex)) {
      if (matchEmojiInURL = match[4].match(emojiRegex)) {
        if ((emojiCode = emojiMap[matchEmojiInURL[0]]) &&
            (emojiCoords = getEmojiSpritesheetCoords(emojiCode))) {

          emojiTitle = encodeEntities(emojiData[emojiCode][1][0]);
          emojiFound = true;

          html.push(encodeEntities(match[0].substr(0, matchEmojiInURL.index)));
          html.push(
              '<span class="emoji emoji-',
              emojiCoords.category,
              '-',
              (emojiIconSize * emojiCoords.column),
              '-',
              (emojiIconSize * emojiCoords.row),
              '" ',
              'title="',emojiTitle, '">',
              ':', emojiTitle, ':</span>'
          );
          html.push(encodeEntities(match[0].substr(matchEmojiInURL.index + matchEmojiInURL[0].length, match[0].length)));
        } else {
          html.push(encodeEntities(matchEmojiInURL[0]));
        }
      }
    } else {
      if (emailRegex.test(match[4])) {
        html.push(
            '<a href="',
            encodeEntities('mailto:' + match[4]),
            '" target="_blank">',
            encodeEntities(match[4]),
            '</a>'
        );
      } else {
        var url = false,
            protocol = match[5],
            tld = match[6],
            excluded = '';

        if (tld) {
          if (!protocol && (tld.substr(0, 4) === 'xn--' || Config.TLD.indexOf(tld.toLowerCase()) !== -1)) {
            protocol = 'http://';
          }

          if (protocol) {
            var balanced = checkBrackets(match[4]);

            if (balanced.length !== match[4].length) {
              excluded = match[4].substring(balanced.length);
              match[4] = balanced;
            }

            url = (match[5] ? '' : protocol) + match[4];
          }
        } else { // IP address
          url = (match[5] ? '' : 'http://') + match[4];
        }

        if (url) {
          html.push(
              '<a href="',
              encodeEntities(url),
              '" target="_blank">',
              encodeEntities(match[4]),
              '</a>',
              excluded
          );

          if (options.extractUrlEmbed &&
              !options.extractedUrlEmbed) {
            options.extractedUrlEmbed = findExternalEmbed(url);
          }
        } else {
          html.push(encodeEntities(match[0]));
        }
      }
    }
  } else {
    html.push(encodeEntities(match[0]));
  }
}