docs: function encodeArray(source) {
          var result = ["["], 
              l = source.length,
              preComma, i, item;
              
          for (i = 0; i < l; i++) {
              item = source[i];
              
              switch (typeof item) {
              case "undefined":
              case "function":
              case "unknown":
                  break;
              default:
                  if(preComma) {
                      result.push(',');
                  }
                  result.push(baidu.json.stringify(item));
                  preComma = 1;
              }
          }
          result.push("]");
          return result.join("");
      }