Most control characters and unicode compatibility characters are not allowed 大多数控制字符和unicode兼容性字符都不允许使用。
2.
Content within cdata sections must be within the range of characters permitted for xml content ; control characters and compatibility characters cannot be escaped this way Cdata节中的内容必须在xml内容允许的字符范围内；控制字符和兼容性字符不能通过这种方式转义。
