code: function (paramName, url) {
  
              var i, len, idx, queryString, params, tokens;
  
              url = url || top.location.href;
  
              idx = url.indexOf("?");
              queryString = idx >= 0 ? url.substr(idx + 1) : url;
  
              // Remove the hash if any
              idx = queryString.lastIndexOf("#");
              queryString = idx >= 0 ? queryString.substr(0, idx) : queryString;
  
              params = queryString.split("&");
  
              for (i = 0, len = params.length; i < len; i++) {
                  tokens = params[i].split("=");
                  if (tokens.length >= 2) {
                      if (tokens[0] === paramName) {
                          return unescape(tokens[1]);
                      }
                  }
              }
  
              return null;
          }
docs: Returns the value of the specified query string parameter.
  This method is not used internally by the Browser History Manager.
  However, it is provided here as a helper since many applications
  using the Browser History Manager will want to read the value of
  url parameters to initialize themselves.
  
  @method getQueryStringParameter
  @param {string} paramName Name of the parameter we want to look up.
  @param {string} queryString Optional URL to look at. If not specified,
  this method uses the URL in the address bar.
  @return {string} The value of the specified parameter, or null.
  @public