code: function encodeProblemUrlChars(url) {
              if (!url)
                  return "";
  
              var len = url.length;
  
              return url.replace(_problemUrlChars, function (match, offset) {
                  if (match == "~D") // escape for dollar
                      return "%24";
                  if (match == ":") {
                      if (offset == len - 1 || /[0-9\/]/.test(url.charAt(offset + 1)))
                          return ":"
                  }
                  return "%" + match.charCodeAt(0).toString(16);
              });
          }
docs: hex-encodes some unusual "problem" chars in URLs to avoid URL detection problems