code: function(str) {
          if (!this.format) {
              this.format = new OpenLayers.Format.JSON();
          }
          this.json = this.format.read(str);
      }
docs: Method: parseData
  Parse the JSON from a request
  
  Parameters:
  str - {String} UTFGrid as a JSON string.
  
  Returns:
  {Object} parsed javascript data