The "charset" parameter is used with some media types to define the character set (section 3.4) of the data. When no explicit charset parameter is provided by the sender, media subtypes of the "text" type are defined to have a default charset value of "ISO-8859-1" when received via HTTP. Data in character sets other than "ISO-8859-1" or its subsets MUST be labeled with an appropriate charset value. See section 3.4.1 for compatibility problems.
The HTTP protocol ([RFC2616] [w3.org], section 3.7.1) mentions ISO-8859-1 as a default character encoding when the "charset" parameter is absent from the "Content-Type" header field. In practice, this recommendation has proved useless because some servers don't allow a "charset" parameter to be sent, and others may not be configured to send the parameter. Therefore, user agents must not assume any default value for the "charset" parameter.
HTTP応答ヘッダー (スコア:1)
* 今までいい加減に済ませていたHTTP応答ヘッダーのツケが出てきた。
* 今まで勝手に中身を判断する悪しき挙動に身を染めていたIEがまっとうになろうとして失敗した。
と、いうあたりだろうな。
Re: (スコア:0)
The "charset" parameter is used with some media types to define the
character set (section 3.4) of the data. When no explicit charset
parameter is provided by the sender, media subtypes of the "text"
type are defined to have a default charset value of "ISO-8859-1" when
received via HTTP. Data in character sets other than "ISO-8859-1" or
its subsets MUST be labeled with an appropriate charset value. See
section 3.4.1 for compatibility problems.
専用のサーバーならともかくこの要求無理だろ
Re:HTTP応答ヘッダー (スコア:2)
しかし一方でHTML4.01のSpecifying the character encoding [w3.org]ではこう書かれています。
つまり、charsetが省略されていた場合は、ユーザエージェントはデフォルト値を仮定してはならない(MUST NOT。HTML 4.01ではMUST NOT等は小文字で表記すると規定されている)としています。