gistfile1.js

var target = target || "_blank";
  var re = new RegExp("\\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`!()\[\]{};:\'\".,<>?]))","g");

  text = "<a target=\"_blank\" href=\"http://www.google.com/\">http://www.google.com/</a>" + 
             " <a target=\"_blank\" href=\"http://www.desk.com/\">http://www.desk.com/</a>"

  text = text.replace(re, function(str) {
    var left  = RegExp.leftContext; 
    // Chrome sometimes throws an exception when calling rightContext
    // var right; try { right = RegExp.rightContext; } catch(e) { right = ""; };
    var right = RegExp.rightContext || "";
    if (is_auto_linked(left, right)) {
      return str;
    }

    return "blah";
  });