diff --git a/doc/dom.md b/doc/dom.md
index 24f1a39..cb25fc4 100644
--- a/doc/dom.md
+++ b/doc/dom.md
@@ -115,6 +115,7 @@ Parse flags                   | Meaning
 `kParseIterativeFlag`         | Iterative(constant complexity in terms of function call stack size) parsing.
 `kParseStopWhenDoneFlag`      | After parsing a complete JSON root from stream, stop further processing the rest of stream. When this flag is used, parser will not generate `kParseErrorDocumentRootNotSingular` error. Using this flag for parsing multiple JSONs in the same stream.
 `kParseFullPrecisionFlag`     | Parse number in full precision (slower). If this flag is not set, the normal precision (faster) is used. Normal precision has maximum 3 [ULP](http://en.wikipedia.org/wiki/Unit_in_the_last_place) error.
+`kParseCommentsFlag`          | Allow one-line `// ...` and multi-line `/* ... */` comments (relaxed JSON syntax).
 
 By using a non-type template parameter, instead of a function parameter, C++ compiler can generate code which is optimized for specified combinations, improving speed, and reducing code size (if only using a single specialization). The downside is the flags needed to be determined in compile-time.
 
diff --git a/doc/dom.zh-cn.md b/doc/dom.zh-cn.md
index bb4eafb..2adf343 100644
--- a/doc/dom.zh-cn.md
+++ b/doc/dom.zh-cn.md
@@ -115,6 +115,7 @@ GenericDocument& GenericDocument::Parse(const Ch* str);
 `kParseIterativeFlag`         | 迭代式（调用堆栈大小为常数复杂度）解析。
 `kParseStopWhenDoneFlag`      | 当从流解析了一个完整的JSON根节点之后，停止继续处理余下的流。当使用了此标志，解析器便不会产生`kParseErrorDocumentRootNotSingular`错误。可使用本标志去解析同一个流里的多个JSON。
 `kParseFullPrecisionFlag`     | 使用完整的精确度去解析数字（较慢）。如不设置此标节，则会使用正常的精确度（较快）。正常精确度会有最多3个[ULP](http://en.wikipedia.org/wiki/Unit_in_the_last_place)的误差。
+`kParseCommentsFlag`          | 容许单行 `// ...` 及多行 `/* ... */` 注释（放宽的JSON语法）。
 
 由于使用了非类型模板参数，而不是函数参数，C++编译器能为个别组合生成代码，以改善性能及减少代码尺寸（当只用单种特化）。缺点是需要在编译期决定标志。
 
diff --git a/doc/features.md b/doc/features.md
index fc54cd0..6b529a7 100644
--- a/doc/features.md
+++ b/doc/features.md
@@ -23,6 +23,8 @@
 * Support Unicode surrogate.
 * Support null character (`"\u0000"`)
  * For example, `["Hello\u0000World"]` can be parsed and handled gracefully. There is API for getting/setting lengths of string.
+* Support optional relaxed syntax.
+ * Single line (`// ...`) and multiple line (`/* ... */`) comments.
 
 ## Unicode
 
diff --git a/doc/features.zh-cn.md b/doc/features.zh-cn.md
index 3a01a4b..85a7db1 100644
--- a/doc/features.zh-cn.md
+++ b/doc/features.zh-cn.md
@@ -23,6 +23,8 @@
 * 支持Unicod代理对（surrogate pair）。
 * 支持空字符（`"\u0000"`）。
  * 例如，可以优雅地解析及处理`["Hello\u0000World"]`。含读写字符串长度的API。
+* 支持放宽的可选语法
+ * 单行（`// ...`）及多行（`/* ... */`） 注释。
 
 ## Unicode