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A media type is a two-part identifier for file formats on the Internet. The Internet Assigned Numbers Authority (IANA) is the official authority for the standardization and publication of these classifications. Media types were first defined in Request for Comments 2045 in November 1996, at which point they were named ''MIME (Multipurpose Internet Mail Extensions) types''. They became known as ''media types'' when it became apparent that their usage had expanded to protocols which did not relate specifically to mail. ==Naming== A media type is composed of a ''type'', a ''subtype'', and optional parameters. As an example, an HTML file might be designated text/html; charset=UTF-8. In this example text is the type, html is the subtype, and charset=UTF-8 is an optional parameter indicating the character encoding.Media type consists of top-level type name and sub-type name, which is further structured into so-called "trees". Media types can optionally define companion data, known as parameters. top-level type name / subtype name (; parameters )top-level type name / (tree. ) subtype name (+suffix ) (; parameters )The currently registered top-level type names are: application, audio, example, image, message, model, multipart, text, video. Sub-type name typically consists of a media type name, but it may or must also contain other content, such as tree prefix (facet), producer's name, product name or suffix - according to the different rules in registration trees. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Media type」の詳細全文を読む スポンサード リンク
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