How to convert text into HTML links in JavaScript, based on http://daringfireball.net/2010/07/improved_regex_for_matching_urls

1.url.js

var GRUBERS_URL_RE = /\b((?:[a-z][\w-]+:(?:\/{1,3}|[a-z0-9%])|www\d{0,3}[.]|[a-z0-9.\-]+[.][a-z]{2,4}\/)(?:[^\s()<>]+|\(([^\s()<>]+|(\([^\s()<>]+\)))*\))+(?:\(([^\s()<>]+|(\([^\s()<>]+\)))*\)|[^\s`!()\[\]{};:'".,<>?«»“”‘’]))/i;

2.test.js

// Should log a URL
[
	"http://foo.com/blah_blah",
	"http://foo.com/blah_blah/",
	"(Something like http://foo.com/blah_blah)",
	"http://foo.com/blah_blah_(wikipedia)",
	"http://foo.com/more_(than)_one_(parens)",
	"(Something like http://foo.com/blah_blah_(wikipedia))",
	"http://foo.com/blah_(wikipedia)#cite-1",
	"http://foo.com/blah_(wikipedia)_blah#cite-1",
	"http://foo.com/unicode_(✪)_in_parens",
	"http://foo.com/(something)?after=parens",
	"http://foo.com/blah_blah.",
	"http://foo.com/blah_blah/.",
	"<http://foo.com/blah_blah>",
	"<http://foo.com/blah_blah/>",
	"http://foo.com/blah_blah,",
	"http://www.extinguishedscholar.com/wpglob/?p=364.",
	"http://✪df.ws/1234",
	"rdar://1234",
	"rdar:/1234",
	"x-yojimbo-item://6303E4C1-6A6E-45A6-AB9D-3A908F59AE0E",
	"message://%3c330e7f840905021726r6a4ba78dkf1fd71420c1bf6ff@mail.gmail.com%3e",
	"http://➡.ws/䨹",
	"www.c.ws/䨹",
	"<tag>http://example.com</tag>",
	"Just a www.example.com link.",
	"http://example.com/something?with,commas,in,url, but not at end",
	"What about <mailto:gruber@daringfireball.net?subject=TEST> (including brokets).",
	"mailto:name@example.com",
	"bit.ly/foo",
	"“is.gd/foo/”",
	"WWW.EXAMPLE.COM",
	"http://www.asianewsphoto.com/(S(neugxif4twuizg551ywh3f55))/Web_ENG/View_DetailPhoto.aspx?PicId=752",
	"http://www.asianewsphoto.com/(S(neugxif4twuizg551ywh3f55))",
	"http://lcweb2.loc.gov/cgi-bin/query/h?pp/horyd:@field(NUMBER+@band(thc+5a46634))"
].forEach(function (s) {
	var m = s.match(GRUBERS_URL_RE);
	console.log(m ? m[1] : 'fail');
});
// Should fail
[
	"6:00p",
	"filename.txt"
].forEach(function (s) {
	var m = s.match(GRUBERS_URL_RE);
	console.log(m ? 'fail' : 'pass');
});

3.linkify.js

/**
 * Returns the text specified with URLs replaced by an html link.
 * does not honor whitespace. Escapes HTML in result. Example:
 *
 * linkify("Go to twitter.com/rcanine to read my <i>status</i>.");
 * -> "Go to <a href="http://twitter.com/rcanine">twitter.com/rcanine</a>
 * -> to read my &lt;i&gt;status&lt;/i&gt;."
 */
var linkify = (function () {
  var GRUBERS_URL_RE = /\b((?:[a-z][\w-]+:(?:\/{1,3}|[a-z0-9%])|www\d{0,3}[.]|[a-z0-9.\-]+[.][a-z]{2,4}\/)(?:[^\s()<>]+|\(([^\s()<>]+|(\([^\s()<>]+\)))*\))+(?:\(([^\s()<>]+|(\([^\s()<>]+\)))*\)|[^\s`!()\[\]{};:'".,<>?«»“”‘’]))/i,
      HAS_PROTOCOL = /^[a-z][\w-]+:/;
  
  function escapeHTML(text) {
    return text.replace(/&/g, '&amp;').replace(/</g, '&lt;').replace(/"/g, '&quot;').replace(/>/g, '&gt;');
  }
  
  function wordToURL(word, index, array) {
    var m = word.match(GRUBERS_URL_RE),
        result = escapeHTML(word),
        url, escapedURL, text;
    
    if (m) {
      text = escapeHTML(m[1]);
      url = HAS_PROTOCOL.test(text) ? text : 'http://' + text;
      result = result.replace(text, '<a href="' + url + '">' + text + '</a>');
    }
    return result;
  }
  
  var map = Array.prototype.map ? function (arr, callback) {
    return arr.map(callback);
  } : function (arr, callback) {
    var arr2 = [], i, l;
    for (i = 0, l = arr.length; i < l; i = i + 1) {
      arr2[i] = callback(arr[i], i, arr);
    }
    return arr2;
  };
  
  return function (text) {
    return map(text.split(/\s+/), wordToURL).join(' ');
  };
}());